View source for Delaware County, Pennsylvania

{{short description|County in Pennsylvania, United States}}
{{distinguish|text=[[Delaware Valley]], which is the entire Philadelphia metropolitan area}}
{{Use American English|date=June 2025}}
{{Use mdy dates|date=April 2024}}
{{Infobox U.S. county
 | county               = Delaware County
 | type                 = County
 | state                = Pennsylvania
 | seal                 = Delaware County pa seal.jpg
 | flag                 = Flag of Delaware County, Pennsylvania.svg
 | founded date         = September 26
 | founded year         = 1789
 | seat wl              = Media
 | largest city         = [[Upper Darby Township, Pennsylvania|Upper Darby]]
 | city type            = Township
 | other_cities         = [[Chester, Pennsylvania|Chester]]
 | coordinates          =
{{Coord|39.92|-75.40|display=title,inline|type:adm2nd_region:US-PA_source:UScensus1990}}
 | area_total_sq_mi     = 191
 | area_land_sq_mi      = 184
 | area_water_sq_mi     = 6.8
 | area percentage      = 3.5%
 | census yr            = 2020
 | pop                  = 576830
 | pop_est_as_of        = 2023
 | population_est       = 576720 {{loss}}
 | density_sq_mi        = auto
 | web                  = delcopa.gov
 | ex image size        = 260
 | ex image             = Media PA Delco Courthouse South.JPG
 | ex image cap         = Delaware County Courthouse in [[Media, Pennsylvania]]
 | district             = 5th
 | named for            = [[Delaware River]]
 | footnotes            = {{designation list|embed=yes|designation1=Pennsylvania|designation1_date=October 3, 1982<ref name="PAHMDB">{{cite web |url=http://www.portal.state.pa.us/portal/server.pt/community/pennsylvania_historical_marker_program/2539/search_for_historical_markers |title=PHMC Historical Markers Search |publisher=Pennsylvania Historical and Museum Commission |website=Commonwealth of Pennsylvania |format=Searchable database |access-date=February 11, 2015 |archive-date=March 21, 2016 |archive-url=https://web.archive.org/web/20160321233735/http://www.portal.state.pa.us/portal/server.pt/community/pennsylvania_historical_marker_program/2539/search_for_historical_markers }}</ref>}}
}}
{{maplink|frame=yes|zoom=8|id=Q27844|type=shape|text=Interactive map of Delaware County, Pennsylvania}}

'''Delaware County''', colloquially referred to as '''Delco''',<ref>{{cite news|title=Delco Sheriff: Don't fall for jury duty scam|url=http://www.delcotimes.com/general-news/20140626/delco-sheriff-dont-fall-for-jury-duty-scam|work=Delco Times|access-date=July 1, 2014}}; {{cite news|last1=McCrystal|first1=Laura|title=Voting Wards To Be Changed in Delco's Radnor Township|url=http://www.philly.com/philly/news/politics/20140627_Voting_wards_to_be_changed_in_Delco_s_Radnor_Township.html|access-date=July 1, 2014|work=Philly.com|date=June 27, 2014}}; {{cite news|last1=McCrystal|first1=Laura|title=Roadwork in Delco to affect I-95 and I-476 this week|url=http://www.philly.com/philly/news/20140630_Roadwork_in_Delco_to_affect_I-95_and_I-476_this_week.html|access-date=July 1, 2014|work=Philly.com|date=June 30, 2014}}; {{cite news|last1=DaGrassa|first1=Peg|title=Here's the Scoop on Ross, Fresh Stop, KFC and Other Delco Businesses|url=http://www.delconewsnetwork.com/articles/2014/06/27/ridley_town_talk/opinion/doc53adcd52cfc51846556340.txt|access-date=July 1, 2014|work=Delco News Network|date=June 27, 2014}}{{Dead link|date=October 2022 |bot=InternetArchiveBot |fix-attempted=yes }}; {{cite news|last1=Kurtz|first1=Paul|title=Delco Homeless Families Get A Day of Escapist Fun|url=http://philadelphia.cbslocal.com/2014/06/27/delco-homeless-families-get-a-day-of-escapist-fun/|access-date=July 1, 2014|work=CBS Philly|date=June 27, 2014}};{{cite news|title=Delco's bars, taverns are really heating up|url=http://www.delcotimes.com/arts-and-entertainment/20140619/delcos-bars-taverns-are-really-heating-up|access-date=July 1, 2014|work=Delco Times|date=June 16, 2014}}</ref> is in the [[Commonwealth (U.S. state)|Commonwealth]] of [[Pennsylvania]]. With a population of 576,830 as of the 2020 census,<ref>{{cite web |title=Census – Geography Profile: Delaware County, Pennsylvania |url=https://data.census.gov/cedsci/profile?g=0500000US42045|access-date=June 26, 2022}}</ref> it is the [[List of counties in Pennsylvania|fifth-most populous]] county in Pennsylvania and the [[List of counties in Pennsylvania|third-smallest in area]]. The county was created on September 26, 1789, from part of [[Chester County, Pennsylvania|Chester County]] and named for the [[Delaware River]]. The county is part of the [[Delaware Valley|Southeast]] region of the commonwealth.{{efn|Includes Philadelphia, Montgomery, Bucks, Delaware, Chester, Lehigh and Northampton Counties}}

Delaware County borders [[Philadelphia]], the [[List of United States cities by population|nation's sixth-most populous city]], to its northeast. It also is adjacent to the [[consolidated city-county|city-county]] of [[Philadelphia County, Pennsylvania|Philadelphia County]] and is included in the [[Philadelphia]]–[[Camden, New Jersey|Camden]]–[[Wilmington, Delaware|Wilmington]], PA–[[New Jersey|NJ]]–[[Delaware|DE]]–[[Maryland|MD]] [[metropolitan statistical area]]. Its [[county seat]] is [[Media, Pennsylvania|Media]].<ref name="GR6">{{cite web|url=http://www.naco.org/Counties/Pages/FindACounty.aspx |access-date=June 7, 2011 |title=Find a County |website=National Association of Counties |archive-url=https://web.archive.org/web/20110531210815/http://www.naco.org/Counties/Pages/FindACounty.aspx |archive-date=May 31, 2011 }}</ref>

==History==
[[File:Map of the early settlements of Delaware County, Penna.jpg|thumb|Map of the early settlements of Delaware County, Pennsylvania]]
[[File:Chester Courthouse 1724.JPG|thumb|The [[1724 Chester Courthouse|old Chester Courthouse]], built in 1724]]
Delaware County lies in the river and bay drainage area named "Delaware" in honor of [[Thomas West, 3rd Baron De La Warr]], Governor of the nearby English colony of [[Virginia]]. The land was explored by [[Henry Hudson]] in 1609, and over the next several decades it was variously claimed and settled by the [[New Sweden|Swedes]], the [[New Netherland|Dutch]], and the [[Province of Pennsylvania|English]]. Its original human inhabitants were the [[Lenape]] tribe of American Indians.

Once the Dutch were defeated and the extent of [[Province of New York|New York]] was determined, King [[Charles II of England]] made his grant to [[William Penn]] to found the colony which came to be named [[Pennsylvania]]. Penn divided his colony into three counties: Bucks, Philadelphia, and Chester. The riverfront land south of [[Philadelphia]], being the most accessible, was quickly granted and settled. In 1789, the southeastern portion of [[Chester County, Pennsylvania|Chester County]] was divided from the rest and named Delaware County for the [[Delaware River]].

==Geography==
[[File:Bartrams Bridge NRHP.JPG|thumb|[[Bartram's Covered Bridge]], built 1860 west of [[Newtown Township, Delaware County, Pennsylvania|Newtown Square]], crosses [[Crum Creek]] into [[Chester County, Pennsylvania|Chester County]]]]
[[File:NewlinMill.JPG|thumb|[[Newlin Mill Complex|Newlin Mill]], built 1704, on the west branch of Chester Creek, near [[Concordville, Pennsylvania|Concordville]]]]
According to the [[United States Census Bureau|U.S. Census Bureau]], the county has a total area of {{convert|191|sqmi}}, of which {{convert|184|sqmi}} is land and {{convert|6.8|sqmi}} (3.5%) is water.<ref name="GR1">{{cite web|url=http://www2.census.gov/geo/docs/maps-data/data/gazetteer/counties_list_42.txt|website=United States Census Bureau|access-date=March 6, 2015|date=August 22, 2012|title=2010 Census Gazetteer Files}}</ref> It is the third-smallest county in Pennsylvania by area.

Delaware County is roughly diamond- or kite-shaped, with the four sides formed by the [[Chester County, Pennsylvania|Chester County]] boundary to the northwest, the boundary with the state of [[Delaware]], a portion of the "[[Twelve-Mile Circle]]") to the southwest, the [[Delaware River]], forming the border with the state of [[New Jersey]]) to the southeast, and the city of [[Philadelphia]] and [[Montgomery County, Pennsylvania|Montgomery County]] to the east and northeast.

The [[List of U.S. states by elevation|lowest point]] in the state of Pennsylvania is located on the Delaware River in [[Marcus Hook, Pennsylvania|Marcus Hook]] in Delaware County, where it flows out of Pennsylvania and into [[Delaware]]. The highest point in Delaware County is 500 feet at two points southeast of Wyola in Newtown Township.<ref>{{Cite web|url=http://www.dcnr.state.pa.us/topogeo/pub/ic4.pdf|title=Elevations in Pennsylvania|archive-url=https://web.archive.org/web/20011116132201/http://www.dcnr.state.pa.us/topogeo/pub/ic4.pdf |archive-date=November 16, 2001 }}</ref>

Waterways in Delaware County generally flow in a southward direction and ultimately drain into the Delaware River. The waterways are, from west to east: the [[Brandywine Creek (Christina River)|Brandywine River]] (forming a portion of the county's western boundary with Chester County), [[Naaman's Creek]], Stoney Creek, [[Chester Creek]], [[Ridley Creek]], [[Crum Creek]], Muckinipates Creek, [[Darby Creek (Pennsylvania)|Darby Creek]] and [[Cobbs Creek]] (forming a portion of the county's eastern boundary with Philadelphia). Crum Creek was dammed in 1931 near [[Pennsylvania Route 252]] to fill [[Springton Lake]] (also known as Geist Reservoir), an approximately {{convert|391|acre|km2|adj=on}}<ref>{{cite web|url=http://crcwatersheds.org/crum|title=Crum|website=Chester – Ridley – Crum Watersheds Association<!-- Bot generated title -->|archive-url=https://web.archive.org/web/20081016023857/http://crcwatersheds.org/crum|archive-date=October 16, 2008}}</ref> drinking water reservoir maintained by [[Aqua America]], the county's largest lake.

The [[Trainer Refinery]] and the [[Port of Chester]] are located along the shores of the Delaware River.

With its location in the southeastern part of the state, Delaware County is the only county to border both Delaware and New Jersey.

===Adjacent counties===
*[[Montgomery County, Pennsylvania|Montgomery County]] (north)
*[[Philadelphia County, Pennsylvania|Philadelphia County]] (northeast)
*[[Gloucester County, New Jersey]] (southeast)
*[[New Castle County, Delaware]] (southwest)
*[[Chester County, Pennsylvania|Chester County]] (west)

Delaware County is one of four counties in the United States to border a state with which it shares the same name (the other three are [[Nevada County, California]], [[Texas County, Oklahoma]], and [[Ohio County, West Virginia]]).

===National protected areas===
[[File:TinicumNWR.jpg|thumb|[[John Heinz National Wildlife Refuge]]]]
*[[First State National Historical Park]] (part)
*[[John Heinz National Wildlife Refuge]] (part)

===State protected area===
{{convert|2600|acre|km2|0}} of the county are occupied by the [[Ridley Creek State Park]].

==Demographics==
{{US Census population
|1790= 9469
|1800= 12809
|1810= 14734
|1820= 14810
|1830= 17323
|1840= 19791
|1850= 24679
|1860= 30597
|1870= 39403
|1880= 56101
|1890= 74683
|1900= 94762
|1910= 117906
|1920= 173084
|1930= 280264
|1940= 310756
|1950= 414234
|1960= 553154
|1970= 600035
|1980= 555007
|1990= 547651
|2000= 550864
|2010= 558979
|2020= 576830
|align-fn=center
|footnote=U.S. Decennial Census<ref>{{cite web|url=https://www.census.gov/prod/www/decennial.html|title=U.S. Decennial Census|publisher=United States Census Bureau|access-date=May 31, 2017}}</ref><br />1790–1960<ref>{{cite web|url=http://mapserver.lib.virginia.edu/|title=Historical Census Browser|publisher=University of Virginia Library|access-date=May 31, 2017|archive-date=August 11, 2012|archive-url=https://web.archive.org/web/20120811110448/http://mapserver.lib.virginia.edu/|url-status=dead}}</ref> 1900–1990<ref>{{cite web|url=https://www.census.gov/population/cencounts/pa190090.txt|title=Population of Counties by Decennial Census: 1900 to 1990|publisher=United States Census Bureau|access-date=May 31, 2017}}</ref><br />1990–2000<ref>{{cite web|url=https://www.census.gov/population/www/cen2000/briefs/phc-t4/tables/tab02.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.census.gov/population/www/cen2000/briefs/phc-t4/tables/tab02.pdf |archive-date=October 9, 2022 |url-status=live|title=Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000|publisher=United States Census Bureau|access-date=May 31, 2017}}</ref> 2010–2019<ref name="QF">{{cite web |title=State & County QuickFacts |url=http://www.co.delaware.pa.us/planning/demodata/CountywideFactSheet.pdf |publisher=Delaware County |archive-url=https://web.archive.org/web/20170208133232/http://www.co.delaware.pa.us/planning/demodata/CountywideFactSheet.pdf |archive-date=February 8, 2017}}</ref><ref>{{cite web |title=Census 2020 |url=https://www.census.gov/quickfacts/fact/table/delawarecountypennsylvania/PST045219}}</ref>
}}

As of the [[2020 United States census|2020 census]], the county was 63% White non-Hispanic, 22% Black or African American, 0.1% Native American or Alaskan Native, 6.3% Asian, 4.6% Hispanic or Latino, 0.1% Native Hawaiian, and 3.5% were two or more races.

As of the [[2000 United States census|2000 census]], there were 550,864 people, 206,320 households, and 139,472 families residing in the county. The population density was {{convert|2990|PD/sqmi|PD/km2|sp=us|adj=off}}. There were 216,978 housing units at an average density of {{convert|1178|/sqmi|/km2|sp=us|adj=off}}. The racial makeup of the county was 80.3% White, 14.5% African American, 0.1% [[Race (United States Census)|Native American]], 3.3% Asian, <0.1% Pacific Islander, 0.6% from other races, and 1.2% from two or more races. 1.5% of the population were [[Hispanics in the United States|Hispanic]] or [[Hispanic and Latino Americans|Latino]] of any race. 24.6% were of Irish, 17.5% Italian, 10.1% German and 6.7% English ancestry.

There were 206,320 households, out of which 31.5% had children under the age of 18 living with them, 50.8% were married couples living together, 12.9% had a female householder with no husband present, and 32.4% were non-families. 27.6% of all households were made up of individuals, and 11.6% had someone living alone who was 65 years of age or older. The average household size was 2.56 and the average family size was 3.17.

In the county, the population was spread out, with 24.8% under the age of 18, 8.9% from 18 to 24, 28.8% from 25 to 44, 21.9% from 45 to 64, and 15.6% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 91.2 males. For every 100 females age 18 and over, there were 86.9 males.

The median income for a household in the county was $50,092, and the median income for a family was $61,590. Males had a median income of $44,155 versus $31,831 for females. The per capita income for the county was $25,040. About 5.8% of families and 8.0% of the population were below the poverty line, including 10.0% of those under age 18 and 7.1% of those age 65 or over.

===2020 census===
{| class="wikitable"
|+Delaware County Racial Composition<ref>{{Cite web|title =P2 HISPANIC OR LATINO, AND NOT HISPANIC OR LATINO BY RACE – 2020: DEC Redistricting Data (PL 94-171) – Delaware County, Pennsylvania|url=https://data.census.gov/cedsci/table?q=Delaware%20County,%20Pennsylvania&t=Race%20and%20Ethnicity&tid=DECENNIALPL2020.P2}}</ref>
!Race
!Num.
!Perc.
|-
|[[White (U.S. Census)|White]] (NH)
|363,249
|63%
|-
|[[African American (U.S. census)|Black or African American]] (NH)
|127,055
|22%
|-
|[[Native American (U.S. Census)|Native American]] (NH)
|676
|0.12%
|-
|[[Asian (U.S. Census)|Asian]] (NH)
|36,317
|6.3%
|-
|[[Pacific Islander (U.S. Census)|Pacific Islander]] (NH)
|133
|0.02%
|-
|[[Race (United States Census)|Other/Mixed]] (NH)
|22,628
|3.9%
|-
|[[Hispanic (U.S. Census)|Hispanic]] or [[Latino (U.S. Census)|Latino]]
|26,772
|4.6%
|}

==Communities==
[[File:Map of Delaware County Pennsylvania With Municipal and Township Labels.svg|thumb|Map of Delaware County, Pennsylvania with municipal labels showing cities (yellow), boroughs (red), townships (white), and census-designated places (blue)]]
Under Pennsylvania law, there are four types of incorporated municipalities: [[List of cities in Pennsylvania|cities]], [[List of towns and boroughs in Pennsylvania|boroughs]], [[List of townships in Pennsylvania|townships]], and exactly one [[List of towns and boroughs in Pennsylvania#Towns|town]]. There are 49 municipalities in Delaware County:

===City===
*[[Chester, Pennsylvania|Chester]]

===Boroughs===
{{Div col|colwidth=10em}}
* [[Aldan, Pennsylvania|Aldan]]
* [[Brookhaven, Pennsylvania|Brookhaven]]
* [[Chester Heights, Pennsylvania|Chester Heights]]
* [[Clifton Heights, Pennsylvania|Clifton Heights]]
* [[Collingdale, Pennsylvania|Collingdale]]
* [[Colwyn, Pennsylvania|Colwyn]]
* [[Darby, Pennsylvania|Darby]]
* [[East Lansdowne, Pennsylvania|East Lansdowne]]
* [[Eddystone, Pennsylvania|Eddystone]]
* [[Folcroft, Pennsylvania|Folcroft]]
* [[Glenolden, Pennsylvania|Glenolden]]
* [[Lansdowne, Pennsylvania|Lansdowne]]
* [[Marcus Hook, Pennsylvania|Marcus Hook]]
* [[Media, Pennsylvania|Media]] ([[county seat]])
* [[Millbourne, Pennsylvania|Millbourne]]
* [[Morton, Pennsylvania|Morton]]
* [[Norwood, Pennsylvania|Norwood]]
* [[Parkside, Pennsylvania|Parkside]]
* [[Prospect Park, Pennsylvania|Prospect Park]]
* [[Ridley Park, Pennsylvania|Ridley Park]]
* [[Rose Valley, Pennsylvania|Rose Valley]]
* [[Rutledge, Pennsylvania|Rutledge]]
* [[Sharon Hill, Pennsylvania|Sharon Hill]]
* [[Swarthmore, Pennsylvania|Swarthmore]]
* [[Trainer, Pennsylvania|Trainer]]
* [[Upland, Pennsylvania|Upland]]
* [[Yeadon, Pennsylvania|Yeadon]]
{{div col end}}

===Townships===
{{Div col|colwidth=10em}}
* [[Aston Township, Pennsylvania|Aston]]
* [[Bethel Township, Delaware County, Pennsylvania|Bethel]]
* [[Chadds Ford Township, Pennsylvania|Chadds Ford]]
* [[Chester Township, Pennsylvania|Chester]]
* [[Concord Township, Delaware County, Pennsylvania|Concord]]
* [[Darby Township, Pennsylvania|Darby]]
* [[Edgmont Township, Delaware County, Pennsylvania|Edgmont]]
* [[Haverford Township, Delaware County, Pennsylvania|Haverford]]
* [[Lower Chichester Township, Pennsylvania|Lower Chichester]]
* [[Marple Township, Pennsylvania|Marple]]
* [[Middletown Township, Delaware County, Pennsylvania|Middletown]]
* [[Nether Providence Township, Pennsylvania|Nether Providence]]
* [[Newtown Township, Delaware County, Pennsylvania|Newtown]]
* [[Radnor Township, Delaware County, Pennsylvania|Radnor]]
* [[Ridley Township, Pennsylvania|Ridley]]
* [[Springfield Township, Delaware County, Pennsylvania|Springfield]]
* [[Thornbury Township, Delaware County, Pennsylvania|Thornbury]]
* [[Tinicum Township, Delaware County, Pennsylvania|Tinicum]]
* [[Upper Chichester Township, Pennsylvania|Upper Chichester]]
* [[Upper Darby Township, Pennsylvania|Upper Darby]]
* [[Upper Providence Township, Delaware County, Pennsylvania|Upper Providence]]
{{div col end}}

===Census-designated places===
[[Census-designated place]]s are geographical areas designated by the [[United States Census Bureau|U.S. Census Bureau]] for the purposes of compiling demographic data. They are not actual jurisdictions under Pennsylvania law. Other unincorporated communities, such as villages, may be listed here as well.

{{div col}}
*[[Ardmore, Pennsylvania|Ardmore]] (''partially in [[Montgomery County, Pennsylvania|Montgomery County]]'')
*[[Boothwyn, Pennsylvania|Boothwyn]]
*[[Broomall, Pennsylvania|Broomall]]
*[[Bryn Mawr, Pennsylvania|Bryn Mawr]] (''mostly in [[Montgomery County, Pennsylvania|Montgomery County]]'')
*[[Chadds Ford, Pennsylvania|Chadds Ford]] (''mostly in [[Chester County, Pennsylvania|Chester County]]'')
*[[Cheyney, Pennsylvania|Cheyney University]] (''mostly in [[Chester County, Pennsylvania|Chester County]]'')
*[[Dilworthtown, Pennsylvania|Dilworthtown]] (''mostly in [[Chester County, Pennsylvania|Chester County]]'')
*[[Drexel Hill, Pennsylvania|Drexel Hill]]
*[[Folsom, Pennsylvania|Folsom]]
*[[Haverford College, Pennsylvania|Haverford College]] (''partially in [[Montgomery County, Pennsylvania|Montgomery County]]'')
*[[Lima, Pennsylvania|Lima]]
*[[Linwood, Pennsylvania|Linwood]]
*[[Rosemont, Pennsylvania|Rosemont]] (''mostly in [[Montgomery County, Pennsylvania|Montgomery County]]'')
*[[St. Davids, Pennsylvania|St. Davids]]
*[[Village Green-Green Ridge, Pennsylvania|Village Green-Green Ridge]]
*[[Villanova, Pennsylvania|Villanova]] (''partially in [[Montgomery County, Pennsylvania|Montgomery County]]'')
*[[Wayne, Pennsylvania|Wayne]]
*[[Woodlyn, Pennsylvania|Woodlyn]]
{{div col end}}

===Unincorporated communities===
{{div col}}
*[[Brookline, Pennsylvania|Brookline]]
*[[Garrett Hill, Pennsylvania|Garrett Hill]]
*[[Glen Mills, Pennsylvania|Glen Mills]]
*[[Havertown, Pennsylvania|Havertown]]
*[[Llanerch, Pennsylvania|Llanerch]]
*[[Oakmont, Haverford Township, Pennsylvania|Oakmont]]
*[[Radnor, Pennsylvania|Radnor]]
*[[Riddlewood, Pennsylvania|Riddlewood]]
*[[Secane, Pennsylvania|Secane]] 
*[[Thornton, Pennsylvania|Thornton]]
*[[Wallingford, Pennsylvania|Wallingford]]
*[[Wawa, Pennsylvania|Wawa]]
{{div col end}}

===Population ranking===
The population ranking of the following table is based on the [[2020 United States census|2020 census]] of Delaware County.<ref>{{Cite web |last= |first= |title=2020 Census Results |url=https://www.census.gov/2020results |access-date=February 10, 2024 |website=Census.gov}}</ref>

'''†''' ''county seat''
{| class="wikitable sortable"
|-
!Rank
!City/Town/etc.
!Municipal type
!Population (2020 Census)
!Total Area
!Population Density
!Incorporation
!Settlement
|-
|1
|[[Upper Darby Township, Pennsylvania|'''Upper Darby''']]
|Township
| 85,681
| 7.83 sq mi
|{{Pop density|85681|7.83|sqmi|prec=1}}
| 1736
| 1653
|-
|2
|[[Haverford Township, Delaware County, Pennsylvania|'''Haverford''']]
|Township
| 50,431
| 9.95 sq mi
|{{Pop density|50431|9.95|sqmi|prec=1}}
| 1682
| 1682
|-
|3
|[[Radnor Township, Delaware County, Pennsylvania|'''Radnor''']]
|Township
| 33,228
| 13.79 sq mi
|{{Pop density|33228|13.79|sqmi|prec=1}}
| 1684
| 1682
|- style="background:#fffacd;"
| 4
|'''[[Chester, Pennsylvania|Chester]]'''
| City
| 32,605
| 6.00 sq mi
|{{Pop density|32605|6|sqmi|prec=1}}
| 1701 (borough) 1866 (city)
| 1644
|-
|5
|'''[[Ridley Township, Pennsylvania|Ridley]]'''
|Township
| 31,053
| 5.31 sq mi
|{{Pop density|31053|5.31|sqmi|prec=1}}
| 1687
| 1647
|- style="background:honeyDew;"
| 6
|'''[[Drexel Hill, Pennsylvania|Drexel Hill]]'''
| CDP
| 29,181
| 3.20 sq mi
|{{Pop density|29181|3.2|sqmi|prec=1}}
|-
|7
|'''[[Springfield Township, Delaware County, Pennsylvania|Springfield]]'''
|Township
| 25,070
| 6.34 sq mi
|{{Pop density|25070|6.34|sqmi|prec=1}}
| 1686
| 1682
|-
|8
|'''[[Marple Township, Pennsylvania|Marple]]'''
|Township
| 24,214
| 10.52 sq mi
|{{Pop density|24214|10.52|sqmi|prec=1}}
| 1684
| 1684
|-
| 9
|'''[[Concord Township, Delaware County, Pennsylvania|Concord]]'''
|Township
| 18,295
| 13.64 sq mi
|{{Pop density|18295|13.64|sqmi|prec=1}}
| 1683
| 1660
|-
|10
|'''[[Upper Chichester Township, Pennsylvania|Upper Chichester]]'''
|Township
| 16,898
| 6.70 sq mi
|{{Pop density|16987|6.71|sqmi|prec=1}}
| 1759
| 1881
|- 
|11
|'''[[Aston Township, Pennsylvania|Aston]]'''
|Township
| 16,791
| 5.84 sq mi
|{{Pop density|16792|5.83|sqmi|prec=1}}
| 1688
| 1681
|-
|12
|'''[[Middletown Township, Delaware County, Pennsylvania|Middletown]]'''
|Township
| 16,373
| 13.47 sq mi
|{{Pop density|16373|13.47|sqmi|prec=1}}
| 1686
| 1681
|-
| 13
|'''[[Newtown Township, Delaware County, Pennsylvania|Newtown]]'''
|Township
| 15,002
| 10.09 sq mi
|{{Pop density|15002|10.09|sqmi|prec=1}}
| 1684
| 1681
|-
| 14
| '''[[Nether Providence Township, Pennsylvania|Nether Providence]]'''
|Township
| 14,525
| 4.72 sq mi
|{{Pop density|14525|4.72|sqmi|prec=1}}
| 1687
| 1687
|- style="background:honeyDew;"
| 15
|'''[[Ardmore, Pennsylvania|Ardmore]]''' (''partially in Montgomery County'')
| CDP
| 13,566
| 1.97 sq mi
|{{Pop density|13566|1.97|sqmi|prec=1}}

|- style="background:seaShell;"
| 16
|'''[[Yeadon, Pennsylvania|Yeadon]]'''
| Borough
| 12,054
| 1.59 sq mi
|{{Pop density|12054|1.59|sqmi|prec=1}}
| 1893
| 1682
|- style="background:honeyDew;"
| 17
|'''[[Broomall, Pennsylvania|Broomall]]'''
| CDP
| 11,718
| 3.17 sq mi
|{{Pop density|11718|3.17|sqmi|prec=1}}
|- style="background:seaShell;"
| 18
|'''[[Lansdowne, Pennsylvania|Lansdowne]]'''
| Borough
| 11,107
| 1.18 sq mi
|{{Pop density|11107|1.18|sqmi|prec=1}}
| 1893
| 1732
|-
| 19
| '''[[Upper Providence Township, Delaware County, Pennsylvania|Upper Providence]]'''
|Township
| 10,852
| 5.81 sq mi
|{{Pop density|10852|5.81|sqmi|prec=1}}
| 1687
| 
|- style="background:seaShell;"
| 20
|'''[[Darby, Pennsylvania|Darby]]'''
| Borough
| 10,715
| 0.84 sq mi
|{{Pop density|10715|0.84|sqmi|prec=1}}
| 1653
| 
|- style="background:honeyDew;"
| 21
|'''[[Woodlyn, Pennsylvania|Woodlyn]]'''
| CDP
| 9,685
| 1.7 sq mi
|{{Pop density|9685|1.7|sqmi|prec=1}}
|- 
| 22
| '''[[Bethel Township, Delaware County, Pennsylvania|Bethel]]'''
|Township
| 9,574
| 5.41 sq mi
|{{Pop density|9574|5.41|sqmi|prec=1}}
| 1683
| 1682
|-
| 23
|'''[[Darby Township, Pennsylvania|Darby]]'''
|Township
|9,219
| 1.42 sq mi
|{{Pop density|9219|1.42|sqmi|prec=1}}
| 1683
| 1682
|- style="background:seaShell;"
| 24
|'''[[Collingdale, Pennsylvania|Collingdale]]'''
| Borough
| 8,908
| 0.87 sq mi
|{{Pop density|8908|0.87|sqmi|prec=1}}
| 1891
| 
|- style="background:seaShell;"
| 25
|'''[[Brookhaven, Pennsylvania|Brookhaven]]'''
| Borough
| 8,300
| 1.71 sq mi
|{{Pop density|8300|1.7|sqmi|prec=1}}
| 1945
| 1684
|- style="background:honeyDew;"
| 26
|'''[[Folsom, Pennsylvania|Folsom]]'''
| CDP
| 8,287
| 1.25 sq mi
|{{Pop density|8287|1.25|sqmi|prec=1}}
|- style="background:honeyDew;"
| 27
|'''[[Villanova, Pennsylvania|Villanova]]''' (''partially in Montgomery County'')
| CDP
| 8,213
| 2.09 sq mi
|{{Pop density|8213|2.09|sqmi|prec=1}}
|- style="background:honeyDew;"
| 28
|'''[[Village Green-Green Ridge, Pennsylvania|Village Green-Green Ridge]]'''
| CDP
| 8,000
| 1.9 sq mi
|{{Pop density|8000|1.9|sqmi|prec=1}}
|- style="background:seaShell;"
| 29
|'''[[Glenolden, Pennsylvania|Glenolden]]'''
| Borough
| 7,223
| 0.97 sq mi
|{{Pop density|7223|0.97|sqmi|prec=1}}
| 1894
| 
|- style="background:seaShell;"
| 30
|'''[[Ridley Park, Pennsylvania|Ridley Park]]'''
| Borough
| 7,186
| 1.08 sq mi
|{{Pop density|7186|1.08|sqmi|prec=1}}
| 1897
| 
|- style="background:honeyDew;"
| 31
|'''[[Wayne, Pennsylvania|Wayne]]'''
| CDP
| 7,160
| 2.12 sq mi
|{{Pop density|7160|2.12|sqmi|prec=1}}
|-
| 32
|'''[[Thornbury Township, Delaware County, Pennsylvania|Thornbury]]'''
|Township
|6,904
| 9.27 sq mi
|{{Pop density|6904|9.27|sqmi|prec=1}}
| 1687
| 
|- style="background:seaShell;"
| 33
|'''[[Clifton Heights, Pennsylvania|Clifton Heights]]'''
| Borough
| 6,863
| 0.63 sq mi
|{{Pop density|6863|0.63|sqmi|prec=1}}
| 1885
| 
|- style="background:seaShell;"
| 34
|'''[[Folcroft, Pennsylvania|Folcroft]]'''
| Borough
| 6,792
| 1.42 sq mi
|{{Pop density|6792|1.42|sqmi|prec=1}}
| 1922
| 
|- style="background:seaShell;"
| 35
|'''[[Swarthmore, Pennsylvania|Swarthmore]]'''
| Borough
| 6,543
| 1.40 sq mi
|{{Pop density|6543|1.40|sqmi|prec=1}}
| 1893
| 1724
|- style="background:seaShell;"
| 36
|'''[[Prospect Park, Pennsylvania|Prospect Park]]'''
| Borough
| 6,427
| 0.74 sq mi
|{{Pop density|6427|0.74|sqmi|prec=1}}
| 1894
| 1694
|- style="background:seaShell;"
| 37
|'''[[Sharon Hill, Pennsylvania|Sharon Hill]]'''
| Borough
| 6,014
| 0.77 sq mi
|{{Pop density|6014|0.77|sqmi|prec=1}}
| 1890
| 
|- style="background:seaShell;"
| 38
|'''[[Norwood, Pennsylvania|Norwood]]'''
| Borough
| 5,943
| 0.82 sq mi
|{{Pop density|5943|0.82|sqmi|prec=1}}
| 1893
| 
|- style="background:seaShell;"
| 39
|'''† [[Media, Pennsylvania|Media]]'''
| Borough
| 5,901
| 0.77 sq mi
|{{Pop density|5901|0.77|sqmi|prec=1}}
| 1850
| 1681
|- style="background:honeyDew;"
| 40
|'''[[Bryn Mawr, Pennsylvania|Bryn Mawr]]''' (''mostly in Montgomery County'')
| CDP
| 5,879
| 0.96 sq mi
|{{Pop density|5879|0.96|sqmi|prec=1}}
|- style="background:honeyDew;"
| 41
|'''[[Boothwyn, Pennsylvania|Boothwyn]]'''
| CDP
| 4,968
| 1.25 sq mi
|{{Pop density|4968|1.25|sqmi|prec=1}}
|-
| 42
|'''[[Edgmont Township, Delaware County, Pennsylvania|Edgmont]]'''
|Township
|4,283
| 9.73 sq mi
|{{Pop density|4283|9.73|sqmi|prec=1}}
| 1687
| 1687
|- style="background:seaShell;"
| 43
|'''[[Aldan, Pennsylvania|Aldan]]'''
| Borough
| 4,244
| 0.60 sq mi
|{{Pop density|4244|0.6|sqmi|prec=1}}
| 1893
| 
|-
| 44
| '''[[Chester Township, Pennsylvania|Chester]]'''
|Township
| 4,080
| 1.43 sq mi
|{{Pop density|4080|1.43|sqmi|prec=1}}
| 1683
| 
|-
| 45
|'''[[Tinicum Township, Delaware County, Pennsylvania|Tinicum]]'''
|Township
|3,983
| 8.78 sq mi
|{{Pop density|3983|8.78|sqmi|prec=1}}
| 1780
| 1643
|-
| 46
| '''[[Chadds Ford Township, Pennsylvania|Chadds Ford]]'''
|Township
| 3,972
| 8.72 sq mi
|{{Pop density|3972|8.72|sqmi|prec=1}}
| 1684
| 
|- style="background:honeyDew;"
| 47
|'''[[Linwood, Pennsylvania|Linwood]]'''
| CDP
| 3,949
| 0.65 sq mi
|{{Pop density|3949|0.65|sqmi|prec=1}}
|- style="background:honeyDew;"
| 48
|'''[[St. Davids, Pennsylvania|St. Davids]]'''
| CDP
| 3,604
| 1.5 sq mi
|{{Pop density|3604|1.5|sqmi|prec=1}}
|- style="background:honeyDew;"
| 49
|'''[[Rosemont, Pennsylvania|Rosemont]]''' (''mostly in Montgomery County'')
| CDP
| 3,507
| 0.82 sq mi
|{{Pop density|3507|0.82|sqmi|prec=1}}
|-
| 50
|'''[[Lower Chichester Township, Pennsylvania|Lower Chichester]]'''
|Township
|3,425
| 1.07 sq mi
|{{Pop density|3425|1.07|sqmi|prec=1}}
| 1682
| 16678
|- style="background:seaShell;"
| 51
|'''[[Upland, Pennsylvania|Upland]]'''
| Borough
| 3,068
| 0.65 sq mi
|{{Pop density|3068|0.65|sqmi|prec=1}}
| 1869
| 1683
|- style="background:seaShell;"
| 52
|'''[[Chester Heights, Pennsylvania|Chester Heights]]'''
| Borough
| 2,897
| 2.22 sq mi
|{{Pop density|2897|2.22|sqmi|prec=1}}
| 1945
| 
|- style="background:seaShell;"
| 53
|'''[[Morton, Pennsylvania|Morton]]'''
| Borough
| 2,778
| 0.36 sq mi
|{{Pop density|2778|0.36|sqmi|prec=1}}
| 1898
| 
|- style="background:honeyDew;"
| 54
|'''[[Lima, Pennsylvania|Lima]]'''
| CDP
| 2,745
| 1.47 sq mi
|{{Pop density|2745|1.47|sqmi|prec=1}}
|- style="background:seaShell;"
| 55
|'''[[East Lansdowne, Pennsylvania|East Lansdowne]]'''
| Borough
| 2,714
| 0.21 sq mi
|{{Pop density|2714|0.21|sqmi|prec=1}}
| 1911
| 
|- style="background:seaShell;"
| 56
|'''[[Colwyn, Pennsylvania|Colwyn]]'''
| Borough
| 2,474
| 0.26 sq mi
|{{Pop density|2474|0.26|sqmi|prec=1}}
| 1892
| 
|- style="background:seaShell;"
| 57
|'''[[Eddystone, Pennsylvania|Eddystone]]'''
| Borough
| 2,459
| 1.52 sq mi
|{{Pop density|2459|1.52|sqmi|prec=1}}
| 1888
| 1641
|- style="background:seaShell;"
| 58
|'''[[Marcus Hook, Pennsylvania|Marcus Hook]]'''
| Borough
| 2,454
| 1.62 sq mi
|{{Pop density|2454|1.62|sqmi|prec=1}}
| 1892
| 
|- style="background:seaShell;"
| 59
|'''[[Parkside, Pennsylvania|Parkside]]'''
| Borough
| 2,321
| 0.21 sq mi
|{{Pop density|2321|0.21|sqmi|prec=1}}
| 1945
| 
|- style="background:seaShell;"
| 60
|'''[[Trainer, Pennsylvania|Trainer]]'''
| Borough
| 1,976
| 1.38 sq mi
|{{Pop density|1976|1.38|sqmi|prec=1}}
| 1919
| 
|- style="background:honeyDew;"
| 61
|'''[[Haverford College, Pennsylvania|Haverford College]]''' (''partially in Montgomery County'')
| CDP
| 1,497
| 0.31 sq mi
|{{Pop density|1497|0.31|sqmi|prec=1}}
|- style="background:honeyDew;"
| 62
|'''[[Chadds Ford, Pennsylvania|Chadds Ford]]''' (''mostly in Chester County'')
| CDP
| 1,476
| 2.28 sq mi
|{{Pop density|1476|2.28|sqmi|prec=1}}
|- style="background:seaShell;"
| 63
|'''[[Millbourne, Pennsylvania|Millbourne]]'''
| Borough
| 1,212
| 0.07 sq mi
|{{Pop density|1212|0.074|sqmi|prec=1}}
| 1909
| 1682
|- style="background:seaShell;"
| 64
|'''[[Rose Valley, Pennsylvania|Rose Valley]]'''
| Borough
| 1,017
| 0.73 sq mi
|{{Pop density|1017|0.73|sqmi|prec=1}}
| 1923
| 1682
|- style="background:honeyDew;"
| 65
|'''[[Dilworthtown, Pennsylvania|Dilworthtown]]''' (''mostly in Chester County'')
| CDP
| 1,150
| 0.64 sq mi
|{{Pop density|1150|0.64|sqmi|prec=1}}
|- style="background:seaShell;"
| 66
|'''[[Rutledge, Pennsylvania|Rutledge]]'''
| Borough
| 782
| 0.14 sq mi
|{{Pop density|782|0.14|sqmi|prec=1}}
| 1887
| 1885
|- style="background:honeyDew;"
| 67
|'''[[Cheyney, Pennsylvania|Cheyney University]]''' (''mostly in Chester County'')
| CDP
| 565
| 0.30 sq mi
|{{Pop density|565|0.30|sqmi|prec=1}}
|}

==Politics and government==
{{PresHead|place=Delaware County, Pennsylvania|source=<ref>{{cite web|url=http://uselectionatlas.org/RESULTS|title=Dave Leip's Atlas of U.S. Presidential Elections|first=David|last=Leip|website=uselectionatlas.org|access-date=November 25, 2018}}</ref>}}
<!-- PresRow should be {{PresRow|Year|Winning party|GOP vote #|Dem vote #|3rd party vote #|State}} -->
{{PresRow|2024|Democratic|123,421|201,324|4,470|Pennsylvania}}
{{PresRow|2020|Democratic|118,639|206,709|4,056|Pennsylvania}}
{{PresRow|2016|Democratic|110,667|177,402|11,267|Pennsylvania}}
{{PresRow|2012|Democratic|110,853|171,792|2,919|Pennsylvania}}
{{PresRow|2008|Democratic|115,273|178,870|3,367|Pennsylvania}}
{{PresRow|2004|Democratic|120,425|162,601|1,512|Pennsylvania}}
{{PresRow|2000|Democratic|105,836|134,861|7,380|Pennsylvania}}
{{PresRow|1996|Democratic|92,628|115,946|26,174|Pennsylvania}}
{{PresRow|1992|Democratic|108,587|111,210|46,277|Pennsylvania}}
{{PresRow|1988|Republican|147,656|96,144|2,505|Pennsylvania}}
{{PresRow|1984|Republican|161,754|98,207|1,821|Pennsylvania}}
{{PresRow|1980|Republican|143,282|88,314|25,263|Pennsylvania}}
{{PresRow|1976|Republican|148,679|117,252|4,963|Pennsylvania}}
{{PresRow|1972|Republican|175,414|94,144|4,893|Pennsylvania}}
{{PresRow|1968|Republican|133,777|106,695|25,964|Pennsylvania}}
{{PresRow|1964|Democratic|111,189|147,189|717|Pennsylvania}}
{{PresRow|1960|Republican|135,672|124,629|482|Pennsylvania}}
{{PresRow|1956|Republican|143,663|82,024|523|Pennsylvania}}
{{PresRow|1952|Republican|129,743|80,316|689|Pennsylvania}}
{{PresRow|1948|Republican|93,412|57,156|2,747|Pennsylvania}}
{{PresRow|1944|Republican|78,533|64,021|755|Pennsylvania}}
{{PresRow|1940|Republican|80,158|60,225|549|Pennsylvania}}
{{PresRow|1936|Republican|74,899|65,117|2,997|Pennsylvania}}
{{PresRow|1932|Republican|75,291|32,413|2,705|Pennsylvania}}
{{PresRow|1928|Republican|83,092|29,378|471|Pennsylvania}}
{{PresRow|1924|Republican|41,998|6,368|2,979|Pennsylvania}}
{{PresRow|1920|Republican|34,126|9,602|1,565|Pennsylvania}}
{{PresRow|1916|Republican|16,315|7,742|677|Pennsylvania}}
{{PresRow|1912|Republican|8,418|6,001|8,819|Pennsylvania}}
{{PresRow|1908|Republican|15,184|5,727|550|Pennsylvania}}
{{PresRow|1904|Republican|15,032|3,586|618|Pennsylvania}}
{{PresRow|1900|Republican|13,794|4,249|358|Pennsylvania}}
{{PresRow|1896|Republican|13,979|4,169|424|Pennsylvania}}
{{PresRow|1892|Republican|9,272|5,520|477|Pennsylvania}}
{{PresRow|1888|Republican|8,791|5,028|351|Pennsylvania}}
{{PresRow|1884|Republican|7,512|4,538|211|Pennsylvania}}
{{PresRow|1880|Republican|7,008|4,473|38|Pennsylvania}}
|}
{{U.S. SenHead|place=Delaware County, Pennsylvania|Seat=1|source=<ref>{{cite news |title=2024 Senate Election (Official Returns) |website=Commonwealth of Pennsylvania by county |date=November 5, 2024 |access-date=December 5, 2024 |url=https://www.nbcnews.com/politics/2024-elections/pennsylvania-senate-results}}</ref>}}
<!-- U.S. SenRow should be {{U.S. SenRow|Year|Winning party|GOP vote #|Dem vote #|3rd party vote #|State}} -->
{{U.S. SenRow|2024|Democratic|121,482|197,424|7,551|Pennsylvania}}
{{U.S. SenFoot}}
The county has operated under a home-rule charter with five at-large council-members since 1972.

Until the 1990s, Delaware County was regarded as a classic suburban Republican county. The Delaware County Republican [[political machine]] was controlled by William McClure and his son [[John J. McClure]] from 1875 to 1965.<ref>{{cite book |last1=McLarnon |first1=John Morrison |title=Ruling Suburbia: John J. McClure and the Republican Machine in Delaware County |date=2003 |publisher=University of Delaware Press |location=Newark, Delaware |isbn=0-87413-814-0 |page=11 |url=https://books.google.com/books?id=uVQFw6j-sRQC |access-date=June 28, 2018}}</ref> Delaware County voted for the Republican candidate all but once from 1860 through 1988, with the exception being [[Lyndon Johnson]]'s national landslide of [[1964 United States presidential election in Pennsylvania|1964]].

In 1992, however, the county swung from a 21-point win for [[George H. W. Bush]] to a narrow one-point win for [[Bill Clinton]], who became only the second Democrat to win the county in the 20th century. Clinton won it just under 10 points in 1996, coming up just short of a majority. The county has gone Democratic in every Presidential election since then by 10 points or more by progressively-increasing margins. In the [[2004 United States presidential election|2004 election]] Democratic presidential candidate [[John Kerry]] won the county by 14 points. [[Barack Obama]] won it by large 21-point margins in each of his bids for president. [[Hillary Clinton]] carried it by an equally substantial 22 points in 2016. [[Joe Biden]] carried it in 2020 with 62 percent of the vote, his second-strongest performance in Pennsylvania. [[Donald Trump]] turned in the worst showing for a Republican in the county in over 160 years.

Driving the county's Democratic shift have been longstanding trends in voter registration advantage and demographics. In 1998, Republicans held a voter registration advantage of about 125,000,<ref>{{cite web|url=https://www.dos.pa.gov/VotingElections/Documents/Elections%20Division/Voter%20Registration%20Statistics/1998%20election%20nov.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.dos.pa.gov/VotingElections/Documents/Elections%20Division/Voter%20Registration%20Statistics/1998%20election%20nov.pdf |archive-date=October 9, 2022 |url-status=live|title=Error}}</ref> but by 2008 that advantage had shrunk to under 20,000 voters.<ref>{{cite web|url=https://www.dos.pa.gov/VotingElections/Documents/Elections%20Division/Voter%20Registration%20Statistics/2008genelectionvoterregistotals.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.dos.pa.gov/VotingElections/Documents/Elections%20Division/Voter%20Registration%20Statistics/2008genelectionvoterregistotals.pdf |archive-date=October 9, 2022 |url-status=live|title = Error}}</ref> As of the [[Judicial elections in Pennsylvania|November 2021 election]], Democrats enjoyed a voter registration advantage of 50,000. Propelling and compounding the voter registration shift has been a change in demographics in the county. Since the [[2000 census (USA)|2000 Census]], the White population of the county has decreased from 80.3% to 68.5% as of the [[2020 United States census|2020 Census]], while, the Black population has risen from 14.5% to 22.7%, driven by the [[gentrification]] of [[Philadelphia]] and [[University City, Philadelphia|University City]] neighborhood and rapid demographic shift in [[Upper Darby]].<ref>http://45.79.181.212:8080/county/PA/Delaware  {{Dead link|date=July 2022}}</ref><ref>{{cite web|url=https://www.census.gov/quickfacts/delawarecountypennsylvania |title=U.S. Census Bureau QuickFacts: Delaware County, Pennsylvania |publisher=Census.gov |date= |access-date=July 20, 2022}}</ref><ref>{{cite news | url=https://whyy.org/articles/northeast-philly-suburbs-become-poorer-as-inner-city-gentrifies/ | title=Northeast Philly, suburbs become poorer as inner city gentrifies | newspaper=Whyy }}</ref> Further increasing the shift has been the change in education level demographics in the county, as voters have become more college educated and white collar (and, in turn, less blue collar) over the past few decades.

While the longstanding Republican registration edge has been erased, Republicans still remain competitive with Democrats at the state and local level. Most Republicans from the county tend to be fiscally conservative and socially moderate, as is the case with Republicans from most suburban Philadelphia counties. In the 2004 [[US Senate]] election, Republican [[Arlen Specter]] defeated [[Joe Hoeffel]] but Democrat [[Bob Casey, Jr.]] defeated [[Rick Santorum]] in the 2006 Senate election. All three Democratic state row office candidates carried it in 2008. In 2016, Delaware County elected all Democrats in national office elections except Republican Patrick Meehan (U.S. Representative).<ref>{{cite web|url=http://www.electionreturns.pa.gov/ENR_New/General/CountyResults?countyName=Delaware&ElectionID=undefined&ElectionType=G&IsActive=undefined|title=Pennsylvania Elections – County Results|website=electionreturns.pa.gov|access-date=November 25, 2016|archive-date=November 25, 2016|archive-url=https://web.archive.org/web/20161125112231/http://www.electionreturns.pa.gov/ENR_New/General/CountyResults?countyName=Delaware&ElectionID=undefined&ElectionType=G&IsActive=undefined|url-status=dead}}</ref>

After the election of [[Donald Trump]] in [[2016 United States presidential election|2016]], the county rapidly shifted blue as a result of increased Democratic turnout and less enthusiasm from often less conservative suburban Republicans. In the 2019 elections for the Delaware County Council, Democrats swept the board and elected Monica Taylor, Elaine P. Schaefer, and Christine Reuther, gaining control of the county Council for the first time since the [[American Civil War|Civil War]].<ref>{{cite web | url=https://www.inquirer.com/politics/election/delaware-county-council-race-democrats-republicans-20191106.html | title=Democrats make history by winning control of Delaware County | date=November 5, 2019 }}</ref> This was the first time in history that the county had an all-Democratic Council.<ref>{{cite web|url=https://patch.com/pennsylvania/media/delaware-county-council-election-2019-live-results|title=Democrats Sweep Delaware County Council Race In Historic Election|date=November 5, 2019|website=Media, PA Patch|language=en|access-date=November 23, 2019}}</ref>

As of 2020, all of Delaware County is located in the state's [[Pennsylvania's 5th congressional district|5th congressional district]], represented by Democrat [[Mary Gay Scanlon]]. Prior to 2019, most of Delaware County had been in the [[Pennsylvania's 7th congressional district|7th congressional district]]. The district had been held for 20 years by Republican [[Curt Weldon]] until he was ousted by [[Joe Sestak]], a retired admiral, in the 2006 [[U.S. House of Representatives]] election. Also in the 2006 election, Democrat [[Bryan Lentz]] unseated Republican incumbent State Representative [[Tom Gannon]] in the [[Pennsylvania House of Representatives, District 161|161st House district]]. In 2010 Sestak ran for the [[United States Senate election in Pennsylvania, 2010|senate seat]] vacated by Arlen Specter and was replaced by Republican [[Pat Meehan]], who defeated Lentz, the Democratic candidate. Lentz was replaced in the State House by [[Joe Hackett (Pennsylvania)|Joe Hackett]], a Republican. Meehan represented the 7th district until his resignation on April 27, 2018.<ref name=resigns>{{cite news|last1=Tamari|first1=Jonathan|title=Rep. Pat Meehan resigns; will pay back $39,000 used for harassment settlement|url=http://www.philly.com/philly/news/politics/pat-meehan-pa-resigns-will-pay-back-sexual-harassment-settlement-20180427.html|access-date=April 27, 2018|work=[[The Philadelphia Inquirer]]|date=April 27, 2018}}</ref> Before it was thrown out by a [[Pennsylvania Supreme Court]] decision in 2018, the 7th Congressional District had been regarded one of the most irregularly drawn districts in the nation.<ref name=WashPost>{{cite news|last1=Ingraham|first1=Christopher|title=This is the best explanation of gerrymandering you will ever see|url=https://www.washingtonpost.com/blogs/wonkblog/wp/2015/03/01/this-is-the-best-explanation-of-gerrymandering-you-will-ever-see/|newspaper=[[The Washington Post]]|access-date=March 2, 2015|ref=Web}}</ref>

=== Voter registration ===
{{Pie chart|thumb=right|value1=49.12|value2=35.67|value3=11.27|value4=3.94|caption=Chart of Voter Registration|label1=[[Democratic Party (United States)|Democratic]]|label2=[[Republican Party (United States)|Republican]]|label4=[[Third party (United States)|Other Parties]]|label3=[[Independent (United States)|Independent]]|color1={{party color|Democratic Party (United States)}}|color2={{party color|Republican Party (United States)}}|color3={{party color|Independent (United States)}}|color4={{party color|Green Party (United States)}}}}As of May 19, 2025, there are 407,783 registered voters in Delaware County.<ref name="Voter Registration">{{cite web |author=Pennsylvania Department of State |date=May 19, 2025 |title=Voter registration statistics by county |url=https://www.dos.pa.gov/VotingElections/OtherServicesEvents/VotingElectionStatistics/Pages/VotingElectionStatistics.aspx |url-status=live |archive-url=https://web.archive.org/web/20160817202727/http://www.dos.pa.gov/VotingElections/OtherServicesEvents/VotingElectionStatistics/Documents/currentvotestats.xls |archive-date=August 17, 2016 |access-date=February 5, 2024 |website=dos.pa.gov}}</ref>
*[[Democratic Party (United States)|Democratic]]: 200,307 (49.12%)
*[[Republican Party (United States)|Republican]]: 145,462 (35.67%)
*[[Independent (United States)|Independent]]: 45,950 (11.27%)
*[[Third party (United States)|Third Party]]: 16,064 (3.94%)

===Delaware County Council===
{{As of|2025|9|21|df=US}}:<ref>{{cite web|title=Elected Officials – Delaware County, Pennsylvania|url=https://www.delcopa.gov/electedofficials/index.html|website=delcopa.gov}}</ref>
{| class="wikitable"
|-
! Office !! Holder !! Party
|- {{Party shading/Democratic}}
| Chair || Monica Taylor || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| Vice-chair || Richard Womack || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| Member of Council || Kevin M. Madden || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| Member of Council || Christine Reuther || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| Member of Council || Elaine Paul Schaefer || [[Democratic Party (United States)|Democratic]]
|}

===County row officers===
Row officers, a term unique to Pennsylvania, are a conglomeration of elected officials defined by Article IX, Section 4 of the [[Pennsylvania Constitution]]. This unit of officers includes the position of controller, District Attorney, treasurer, sheriff, register of wills, recorder of deeds, [[Prothonotary|prothonotaries]], clerks of the court, and the coroner. It is thought that this term originated because these positions were arranged in a row on a typical ballot.<ref>{{cite news |url=https://cumberlink.com/news/local/row-officers-what-is-their-role-in-county-government/article_1aa10324-6702-11e4-97b8-2f2e71f054bd.html |url-access=subscription |title=Row officers: What is their role in county government? |first=Daniel |last=Walmer |newspaper=The Sentinel |location=Pennsylvania |date=November 7, 2014 |language=en|access-date=March 2, 2020}}</ref>

{| class="wikitable"
|-
! Office !! Holder !! Party
|- {{Party shading/Democratic}}
| Controller || Joanne Phillips, Esquire || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| District Attorney || Jack Stollsteimer || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| Register of Wills || Vincent A. Rongione, Esquire||[[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| Sheriff || Jerry Sanders|| [[Democratic Party (United States)|Democratic]]
|}

===United States Senate===
{| class="wikitable"
|-
! Senator !! Party
|- {{Party shading/Democratic}}
| [[John Fetterman]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Republican}}
| [[Dave McCormick]] || [[Republican Party (United States)|Republican]]
|}

===United States House of Representatives===
[[File:Pennsylvania Congressional District 5.png|thumb|The 2018 congressional map ordered by the [[Supreme Court of Pennsylvania]] places all of Delaware County in the new [[Pennsylvania's 5th congressional district|5th congressional district]].]]{{As of|2021|7|23|df=US}}:
{| class="wikitable"
|-
! District !! Representative !! Party
|- {{Party shading/Democratic}}
| [[Pennsylvania's 5th congressional district|5]] || [[Mary Gay Scanlon]] || [[Democratic Party (United States)|Democratic]]
|}

===State senate===
{{As of|2021|7|23|df=US}}:
{| class="wikitable"
|-
! District !! Representative !! Party
|- {{Party shading/Democratic}}
| [[Pennsylvania's 8th Senatorial District|8]] || [[Anthony H. Williams|Anthony Hardy Williams]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| [[Pennsylvania's 9th Senatorial District|9]] || [[John I. Kane]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| [[Pennsylvania's 17th Senatorial District|17]] || [[Amanda Cappelletti]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| [[Pennsylvania Senate, District 26|26]] || [[Tim Kearney (politician)|Tim Kearney]] || [[Democratic Party (United States)|Democratic]]
|}

===State House of Representatives===
{{As of|2022|3|2|df=US}}:
{| class="wikitable"
|-
! District !! Representative !! Party
|- {{Party shading/Democratic}}
| [[Pennsylvania's 159th Representative District|159]] || [[Carol Kazeem]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Republican}}
| [[Pennsylvania's 160th Representative District|160]] || [[Wendell Craig Williams|Craig Williams]] || [[Republican Party (United States)|Republican]]
|- {{Party shading/Democratic}}
| [[Pennsylvania's 161st Representative District|161]] || [[Leanne Krueger]]|| [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| [[Pennsylvania's 162nd Representative District|162]] || [[Dave Delloso]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| [[Pennsylvania House of Representatives, District 163|163]] || [[Heather Boyd]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
|[[Pennsylvania's 164th Representative District|164]]|| [[Gina Curry]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| [[Pennsylvania's 165th Representative District|165]] || [[Jennifer O'Mara]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| [[Pennsylvania's 166th Representative District|166]] || [[Greg Vitali]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| [[Pennsylvania's 168th Representative District|168]] || [[Lisa Borowski]] || [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| [[Pennsylvania's 185th Representative District|185]] || [[Regina Young]]|| [[Democratic Party (United States)|Democratic]]
|- {{Party shading/Democratic}}
| [[Pennsylvania's 191st Representative District|191]] || [[Joanna McClinton]] || [[Democratic Party (United States)|Democratic]]
|}

===Corrections===
The [[George W. Hill Correctional Facility]] (Delaware County Prison) is located in [[Thornbury Township, Delaware County, Pennsylvania|Thornbury Township]].<ref name="Thornburystuff">"[http://thornbury.websecurestores.net/LinkClick.aspx?fileticket=tqteHNQKPS8%3d&tabid=78&mid=498 Chapter 7 7–11] {{webarchive|url=https://web.archive.org/web/20120320180858/http://thornbury.websecurestores.net/LinkClick.aspx?fileticket=tqteHNQKPS8=&tabid=78&mid=498 |date=March 20, 2012 }}." Comprehensive Zoning Plan. Thornbury Township. Retrieved on September 6, 2011. "The three major institutions found in the Township, the Delaware County Prison, Glen Mills Schools and Cheyney University[...]"</ref><ref name="HillPrison">{{Cite web |url=http://www.co.delaware.pa.us/depts/prison.html |title=Delaware County Prison |access-date=September 7, 2011 |archive-date=September 2, 2011 |archive-url=https://web.archive.org/web/20110902012508/http://www.co.delaware.pa.us/depts/prison.html |url-status=bot: unknown }}." Delaware County, Pennsylvania. Retrieved on September 6, 2011. "George W. Hill Correctional Facility (Delaware County Prison), which is located on 500 Cheyney Road in Thornbury Township[...]"</ref> The jail houses pre-trial inmates and convicted persons who are serving sentences of no longer than two years less one day.<ref name="HillPrison"/> It is operated by Delaware County.<ref>{{cite news |last1=Cooper |first1=Kenny |title=Delco takes back management of George W. Hill Correctional Facility — now it confronts 'chronic over-incarceration' |url=https://whyy.org/articles/delco-takes-back-management-of-george-w-hill-correctional-facility/ |publisher=WHYY |date=April 6, 2022}}</ref>

==Education==
[[Image:Map of Delaware County Pennsylvania School Districts.png|thumb|Map of Delaware County's school districts]]

===Public school districts===
<!-- New links in alphabetical order please -->
School districts include:<ref>{{cite web|url=https://www2.census.gov/geo/maps/DC2020/PL20/st42_pa/schooldistrict_maps/c42045_delaware/DC20SD_C42045.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www2.census.gov/geo/maps/DC2020/PL20/st42_pa/schooldistrict_maps/c42045_delaware/DC20SD_C42045.pdf |archive-date=October 9, 2022 |url-status=live|title=2020 CENSUS – SCHOOL DISTRICT REFERENCE MAP: Delaware County, PA|publisher=[[U.S. Census Bureau]]|access-date=July 20, 2022}} – [https://www2.census.gov/geo/maps/DC2020/PL20/st42_pa/schooldistrict_maps/c42045_delaware/DC20SD_C42045_SD2MS.txt Text list]</ref>
*[[Chester Upland School District]]
*[[Chichester School District]]
*[[Garnet Valley School District]]
*[[Haverford Township School District]]
*[[Interboro School District]]
*[[Marple Newtown School District]]
*[[Penn-Delco School District]]
*[[Radnor Township School District]]
*[[Ridley School District]]
*[[Rose Tree Media School District]]
*[[Southeast Delco School District]]
*[[Springfield School District (Delaware County)|Springfield School District]]
*[[Upper Darby School District]]
*[[Wallingford-Swarthmore School District]]
*[[West Chester Area School District]]
*[[William Penn School District]]

Note that [[Delaware County Technical High School]] takes students from all of the county.

===Charter schools===
*Chester Community Charter School
*Widener Partnership Charter School
*[[Chester Charter Scholars Academy]]

===Private schools===
In 1963 the [[Roman Catholic Archdiocese of Philadelphia]] had 48 Catholic K-8/elementary schools in Delaware County with a total of 39,695 students, which was the highest ever enrollment. From 1971 to 2012, 20 of these schools closed, with ten of them closing from 2003 to 2012. By 2012 there were 28 Catholic K-8/elementary schools in Delaware County with a total of 8,291 students.<ref name=MengersSeasonofChange>{{cite web|url=https://www.delcotimes.com/news/season-of-change-new-regional-schools-poised-to-replace-long/article_82752938-0714-5283-ba75-b0eaeda6094a.html|title=Season of Change: New regional schools poised to replace long-time Delco Catholic institutions|work=[[Delco Times]]|date=June 10, 2012|access-date=May 3, 2020|archive-date=May 4, 2020|archive-url=https://web.archive.org/web/20200504035835/https://www.delcotimes.com/news/season-of-change-new-regional-schools-poised-to-replace-long/article_82752938-0714-5283-ba75-b0eaeda6094a.html}}</ref> One notable private school is [[Friends School Haverford]].

===Colleges and universities===
[[File:1909 Cheyney Library.JPG|thumb|Library at [[Cheyney University]]]]
[[Image:BWestBplace.JPG|thumb|[[Benjamin West Birthplace]] on the campus of [[Swarthmore College]]]]
[[Image:OldMainWidener.JPG|thumb|Old Main at [[Widener University]]]]
*[[Cabrini University]]
*[[Cheyney University]]
*[[Eastern University (United States)|Eastern University]]
*[[Delaware County Community College]] (locations in Marple Township, Upper Darby and Sharon Hill)
*[[Haverford College]]
*[[Neumann University]]
*[[Pendle Hill Quaker Center for Study and Contemplation]]
*[[Pennsylvania Institute of Technology]]
*[[Penn State Brandywine]]
*[[Rosemont College]]
*[[Swarthmore College]]
*[[Villanova University]]
*[[Widener University]]
*[[Williamson College of the Trades]]

===Adult education===
* Haverford Adult School<ref>{{cite web|url=http://www.haverfordadultschool.org/|title=Haverford Township Adult School|website=Haverford Township Adult School}}</ref>
* Main Line School Night<ref>{{cite web|url=http://www.mainlineschoolnight.org/|title=MainLine School Night -|website=mainlineschoolnight.org}}</ref>
* Senior Community Services Lifelong Learning<ref>{{cite web |url=http://www.scs-delco.org/learning |title=Lifelong Learing Course Catalog &#124; Senior Community Services (SCS) |access-date=March 26, 2010 |archive-url=https://web.archive.org/web/20100325102302/http://www.scs-delco.org/learning |archive-date=March 25, 2010 }}</ref>
* Delaware County Literacy Council

===Libraries===
{{main|List of public libraries in Delaware County, Pennsylvania}}

==Transportation==
[[File:2022-10-07 12 00 42 View south along Interstate 95 (Delaware Expressway) from the pedestrian overpass for Crosby Street in Chester, Delaware County, Pennsylvania.jpg|thumb|[[Interstate 95 in Pennsylvania|I-95]] southbound in Delaware County]]
Delaware County is bisected north to south by [[Interstate 476|Blue Route]] Interstate 476, which connects [[Interstate 76 (Ohio–New Jersey)|I-76]] just north of the extreme northern corner of the county to [[Interstate 95 in Pennsylvania|I-95]], which parallels the [[Delaware River]] along the southeastern edge of the county.

Delaware County is home to [[SEPTA]]'s [[69th Street Transportation Center]] in [[Upper Darby Township, Pennsylvania|Upper Darby]], and is served by the [[Norristown High Speed Line]] (P&W), two Red Arrow trolley lines, [[Media–Sharon Hill Line]], four [[SEPTA Regional Rail|Regional Rail Lines]], including the [[Airport Line (SEPTA)|Airport Line]], [[Wilmington/Newark Line]], [[Media/Wawa Line]], and [[Paoli/Thorndale Line]]), and a host of bus routes.

The western portion of [[Philadelphia International Airport]] is located in Delaware County, and the county hosts some airport-related commerce such as Philadelphia's [[United Parcel Service|UPS]] terminal and airport hotels.

===Major roads and highways===
{{Div col}}
*{{jct|state=PA|I|95}}
*{{jct|state=PA|I|476}}
*{{jct|state=PA|US|1}}
*{{jct|state=PA|US|13}}
*{{jct|state=PA|US|30}} 
*{{jct|state=PA|US|202}}
*{{jct|state=PA|US|322}}
*{{jct|state=PA|PA|3}}
*{{jct|state=PA|PA|252}}
*{{jct|state=PA|PA|261}}
*{{jct|state=PA|PA|291}}
*{{jct|state=PA|PA|320}}
*{{jct|state=PA|PA|352}}
*{{jct|state=PA|PA|420}}
*{{jct|state=PA|PA|452}}
*{{jct|state=PA|PA|491}}
*{{jct|state=PA|PA|926}}
{{div col end}}

==Recreation==
===Parks===
[[File:RCSPSycMillsDam.JPG|thumb|Dam on Ridley Creek in [[Ridley Creek State Park]]]]
[[File:Rose Tree Tavern 2013.JPG|thumb|[[Old Rose Tree Tavern]] in Rose Tree Park]]
There is one [[List of Pennsylvania state parks|Pennsylvania state park]] in Delaware County:
*[[Ridley Creek State Park]]

County parks include:
*[[Clayton Park & Golf Course]]
*[[Glen Providence Park]]
*[[Kent Park/Dog Park]]
*[[Rose Tree Park]]
*[[Smedley Park]]
*[[Upland Park (Pennsylvania)|Upland Park]]

===Racing===
[[Harrah's Philadelphia]] is a [[harness racing]] track and casino (i.e., "racino") located on the Chester, Pennsylvania waterfront. It is owned by [[Vici Properties]] and operated by [[Caesars Entertainment (2020)|Caesars Entertainment]].

==Sports==
[[Chester, Pennsylvania|Chester]] is home to the [[Philadelphia Union]] of [[Major League Soccer]]; the team plays at [[Subaru Park]], a venue located at the base of the [[Commodore Barry Bridge]].

Delaware County is the traditional home of women's professional soccer in the Philadelphia area. The former [[Philadelphia Charge]] of the defunct [[Women's United Soccer Association]] played at [[Villanova Stadium]], which is located on the campus of [[Villanova University]]. The [[Philadelphia Independence]] of [[Women's Professional Soccer]] succeeded the Charge and played at Widener University's Leslie Quick Stadium in 2011.

Delaware County is the home of one of oldest baseball leagues in the country, the Delco League, which at one time was known for featuring future, former, and even current major league players who were offered more money than their current teams would pay them.<ref>{{cite web|url=http://www.leaguelineup.com/information.asp?url=delcoleague |title=Delco League |website=leaguelineup.com |access-date=October 8, 2014 |archive-url=https://web.archive.org/web/20141012091504/http://www.leaguelineup.com/information.asp?url=delcoleague |archive-date=October 12, 2014 }}</ref><ref>{{cite news|url=http://www.delcotimes.com/article/DC/20121011/NEWS/310119998|title=Delco League to honor legends of ballfields from 105 seasons|work=Delco Times|access-date=October 8, 2014}}</ref><ref>{{cite news|url=http://www.delcotimes.com/general-news/20110418/colts-bolt-borough-collingdales-delco-baseball-league-team-is-the-latest-loss-endured-by-tiny-town|title=COLTS BOLT BOROUGH: Collingdale's Delco Baseball League team is the latest loss endured by tiny town|work=Delco Times|access-date=October 8, 2014}}</ref>

Every summer, Delaware County is home to the Delco Pro-Am, a basketball league consisting of current, future, and former NBA players as well as local standout players.<ref>{{cite news|url=http://www.delcotimes.com/article/DC/20130625/NEWS/306259936|title=Plenty of talent as Delco Pro-Am League tips off|work=Delco Times|access-date=October 8, 2014}}</ref>

Delaware County is also the former home of a [[rugby league]] team called the Aston Bulls, a member of the [[American National Rugby League]].

[[Darby, Pennsylvania|Darby]] was home to the [[Hilldale Club]], the [[1925 Colored World Series]] champions.

==Media==
The county is serviced by several newspapers, including ''[[Delaware County Daily Times]]'', ''News of Delaware County'', ''The Spirit'', and ''The Suburban and Wayne Times''.{{citation needed|date=November 2014}}

''[[The Philadelphia Inquirer]]'' also has a significant presence in Delaware County. ''Delaware County Magazine'' is the news magazine with the largest circulation in Delaware County, reaching over 186,000 homes.

==Climate==
Delaware County has two physical geographic regions: the [[Piedmont (United States)|Piedmont]] and the [[Atlantic Coastal Plain]], Most of the county has a [[humid subtropical climate]] (''Cfa'') while some higher northern areas have a hot-summer [[humid continental climate]] (''Dfa''.). The [[hardiness zone]] is mostly 7b except for 7a in areas closer to Chester County (except along the Brandywine Creek) and 8a in Ridley Township near the Delaware River. [https://planthardiness.ars.usda.gov/]

{{Weather box
| width = auto
| single line = Y
| location = Newtown Square (Elevation: {{convert|456|ft|m|abbr=on|disp=semicolon}}) 1981–2010 Averages 
| Jan high F  =   	38.6
| Feb high F  =   	41.8
| Mar high F  =   	50.4
| Apr high F  =   	62.3
| May high F  =   	72.1
| Jun high F  =   	81.0
| Jul high F  =   	85.3
| Aug high F  =   	83.5
| Sep high F  =   	76.8
| Oct high F  =   	65.5
| Nov high F  =   	54.1
| Dec high F  =   	42.6
| year high F =   	62.9
| Jan mean F  =   	30.4
| Feb mean F  =   	33.1
| Mar mean F  =   	40.6
| Apr mean F  =   	51.6
| May mean F  =   	61.2
| Jun mean F  =   	70.5
| Jul mean F  =   	75.2
| Aug mean F  =  	73.7
| Sep mean F  =   	66.3
| Oct mean F  =   	55.0
| Nov mean F  =   	44.8
| Dec mean F  =   	34.6
| year mean F =   	53.2
| Jan low F  =   	22.2
| Feb low F  =   	24.3
| Mar low F  =   	30.9
| Apr low F  =   	40.8
| May low F  =   	50.2
| Jun low F  =   	60.0
| Jul low F  =   	65.1
| Aug low F  =   	63.8
| Sep low F  =   	55.7
| Oct low F  =   	44.4
| Nov low F  =   	35.5
| Dec low F  =   	26.6
| year low F =   	43.4
| precipitation colour = green
| Jan precipitation inch  =   	3.36
| Feb precipitation inch  =   	2.80
| Mar precipitation inch  =   	3.89
| Apr precipitation inch  =   	3.84
| May precipitation inch  =   	4.08
| Jun precipitation inch  =   	3.94
| Jul precipitation inch  =   	4.71
| Aug precipitation inch  =   	3.88
| Sep precipitation inch  =   	4.65
| Oct precipitation inch  =   	3.87
| Nov precipitation inch  =   	3.61
| Dec precipitation inch  =   	3.89
| year precipitation inch =   	46.52
| humidity colour = green
| Jan humidity    =	68.3
| Feb humidity    =	65.0
| Mar humidity    =	60.5
| Apr humidity    =	59.4
| May humidity    =	63.2
| Jun humidity    =	68.2
| Jul humidity    =	68.2
| Aug humidity    =	70.5
| Sep humidity    =	71.7
| Oct humidity    =	70.5
| Nov humidity    =	69.7
| Dec humidity    =	70.8
| year humidity   =	67.2
| Jan dew point F =	21.2
| Feb dew point F =	22.6
| Mar dew point F =	28.0
| Apr dew point F =	37.9
| May dew point F =	48.6
| Jun dew point F =	59.5
| Jul dew point F =	64.0
| Aug dew point F =	63.5
| Sep dew point F =	56.9
| Oct dew point F =	45.6
| Nov dew point F =	35.5
| Dec dew point F =	26.1
| year dew point F =	42.5
|source 1 = PRISM<ref name="prism">{{cite web|url=http://prism.oregonstate.edu/explorer/|title=PRISM Climate Group, Oregon State University|access-date=August 9, 2019}}</ref>}}

{{Weather box
| width = auto
| single line = Y
| location = Chester (Elevation: {{convert|10|ft|m|abbr=on|disp=semicolon}}) 1981–2010 Averages 
| Jan high F  =   	40.5
| Feb high F  =   	44.2
| Mar high F  =   	52.0
| Apr high F  =   	63.4
| May high F  =   	73.4
| Jun high F  =   	82.7
| Jul high F  =   	87.0
| Aug high F  =   	85.2
| Sep high F  =   	78.3
| Oct high F  =   	66.7
| Nov high F  =   	56.1
| Dec high F  =   	45.0
| year high F =   	64.6
| Jan mean F  =   	33.7
| Feb mean F  =   	36.5
| Mar mean F  =   	43.7
| Apr mean F  =   	54.3
| May mean F  =   	64.1
| Jun mean F  =   	73.7
| Jul mean F  =   	78.3
| Aug mean F  =  	76.8
| Sep mean F  =   	69.5
| Oct mean F  =   	58.1
| Nov mean F  =   	48.3
| Dec mean F  =   	38.2
| year mean F =   	56.4
| Jan low F  =   	26.8
| Feb low F  =   	28.9
| Mar low F  =   	35.3
| Apr low F  =   	45.2
| May low F  =   	54.8
| Jun low F  =   	64.6
| Jul low F  =   	69.7
| Aug low F  =   	68.4
| Sep low F  =   	60.7
| Oct low F  =   	49.4
| Nov low F  =   	40.5
| Dec low F  =   	31.4
| year low F =   	48.1
| precipitation colour = green
| Jan precipitation inch  =   	3.15
| Feb precipitation inch  =   	2.70
| Mar precipitation inch  =   	3.87
| Apr precipitation inch  =   	3.62
| May precipitation inch  =   	3.81
| Jun precipitation inch  =   	3.80
| Jul precipitation inch  =   	4.65
| Aug precipitation inch  =   	3.56
| Sep precipitation inch  =   	4.21
| Oct precipitation inch  =   	3.44
| Nov precipitation inch  =   	3.27
| Dec precipitation inch  =   	3.62
| year precipitation inch =   	43.70
| humidity colour = green
| Jan humidity    =	65.3
| Feb humidity    =	60.7
| Mar humidity    =	57.6
| Apr humidity    =	57.2
| May humidity    =	60.8
| Jun humidity    =	62.7
| Jul humidity    =	64.4
| Aug humidity    =	65.8
| Sep humidity    =	67.8
| Oct humidity    =	67.3
| Nov humidity    =	65.3
| Dec humidity    =	65.1
| year humidity   =	63.4
| Jan dew point F =	23.3
| Feb dew point F =	24.2
| Mar dew point F =	29.7
| Apr dew point F =	39.5
| May dew point F =	50.3
| Jun dew point F =	60.2
| Jul dew point F =	65.3
| Aug dew point F =	64.5
| Sep dew point F =	58.4
| Oct dew point F =	47.3
| Nov dew point F =	37.2
| Dec dew point F =	27.5
| year dew point F =	44.0
|source 1 = PRISM<ref name="prism" />}}

==See also==
{{Portal|Philadelphia|Pennsylvania}}
* [[National Register of Historic Places listings in Delaware County, Pennsylvania]]
{{Clear}}

==References==
{{Notelist}}{{reflist}}

==Further reading==
*{{cite book|url=https://archive.org/details/cu31924006215655 |author=Ashmead, Henry Graham|publisher=Hungerford, Austin N|title= History of Delaware County, Pennsylvania|date=1884}}
*{{cite book|url=https://archive.org/details/historyofdelawar03jord|author=Jordan, John W|title=A History of Delaware County, Pennsylvania and Its People|date= 1914|publisher=New York, Lewis Historical Publishing Company}}

==External links==
{{commons category}}
*[https://delcopa.gov/ Official website]

{{Delaware County, Pennsylvania}}
{{Delaware Valley}}
{{Pennsylvania}}
{{Authority control}}

[[Category:Delaware County, Pennsylvania| ]]
[[Category:1789 establishments in Pennsylvania]]
[[Category:Populated places established in 1789]]