View source for Mercer County, Illinois

{{Short description|County in Illinois, United States}}
{{Use American English|date=June 2025}}
{{Use mdy dates|date=April 2024}}
{{Infobox U.S. county
 | county               = Mercer County
 | state                = Illinois
 | ex image             = Mercer County Courthouse Image.jpeg
 | ex image cap         = [[Mercer County Courthouse (Illinois)|Mercer County Courthouse]]
 | founded              = January 13, 1825
 | seat wl              = Aledo
 | largest city wl      = Aledo
 | area_total_sq_mi     = 569
 | area_land_sq_mi      = 561
 | area_water_sq_mi     = 7.5
 | area percentage      = 1.3
 | census yr            = 2020
 | pop                  = 15699
 | pop_est_as_of        = 2024
 | population_est       = 15292 {{loss}}<ref>{{cite web |title=County Population Totals and Components of Change: 2020–2024 |url=https://www.census.gov/data/tables/time-series/demo/popest/2020s-counties-total.html |website=United States Census Bureau |publisher=U.S. Department of Commerce |date=March 2025 |access-date=August 31, 2025}}</ref>
 | density_sq_mi        = auto
 | web  = www.mercercountyil.org
 | district             = 15th
 | district2            = 17th
 | time zone           = Central
 | named for = [[Hugh Mercer]]}}

'''Mercer County''' is a [[County (United States)|county]] in [[Illinois]]. According to the [[2020 United States census|2020 census]], it had a population of 15,699.<ref>{{cite web|title=Mercer County, Illinois|url = https://data.census.gov/profile/Mercer_County,_Illinois?g=050XX00US17131|publisher=[[United States Census Bureau]] |access-date=June 10, 2023}}</ref> Its [[county seat]] is [[Aledo, Illinois|Aledo]].<ref name="GR6">{{cite web|url=http://www.naco.org/Counties/Pages/FindACounty.aspx|access-date=June 7, 2011|title=Find a County|publisher=National Association of Counties}}</ref> Mercer County is included in the [[Davenport, Iowa|Davenport]]-[[Moline, Illinois|Moline]]-[[Rock Island, Illinois|Rock Island]], IA-IL [[Quad Cities|Metropolitan Statistical Area]].<ref>{{cite web|url=https://www.whitehouse.gov/omb/bulletins/fy2006/b06-01.pdf|title=Update of Statistical Area Definitions and Guidance on Their Uses|access-date=July 21, 2006|author=United States Office of Management and Budget|author-link=United States Office of Management and Budget|pages=5, 36|url-status=dead|archive-url = https://web.archive.org/web/20060514003222/http://www.whitehouse.gov/omb/bulletins/fy2006/b06-01.pdf <!-- Bot retrieved archive --> |archive-date = May 14, 2006}}</ref>

==History==
Mercer County is named for [[Hugh Mercer]] (1726–1777), a physician and general during the [[American Revolution]] who died from wounds suffered at the [[Battle of Princeton]].

In May 1812, Congress passed an act which set aside lands in [[Arkansas]], [[Michigan]], and Illinois as payment to volunteer soldiers in the [[War of 1812]]. Mercer County was part of this "Military Tract."

Seven years after Illinois became a state, Mercer County was founded. It was formed from unorganized territory near [[Pike County, Illinois|Pike County]] on January 13, 1825. Although the county had been created, its government was not organized for several years; for administration purposes it was attached first to Schuyler County (until 1826), then to Peoria (until 1831), and finally to Warren County. The organization of the county government was finally completed in 1835, after a large influx of settlers following the [[Black Hawk War]].<ref>Mercer County Fact Sheet, Illinois State Archives.  {{cite web|url=http://www.cyberdriveillinois.com/departments/archives/irad/mercer.html |title=Mercer County Fact Sheet |access-date=October 23, 2007 |url-status=dead |archive-url=https://web.archive.org/web/20071023015434/http://www.cyberdriveillinois.com/departments/archives/irad/mercer.html |archive-date=October 23, 2007 }}</ref>

<gallery>
File:Mercer_County_Illinois_1825.png|Mercer County at the time of its creation in 1825
File:Mercer County Illinois 1827.png|Mercer County in 1827, reduced to its present borders
</gallery>

==Geography==
According to the [[U.S. Census Bureau]], the county has a total area of {{convert|569|sqmi}}, of which {{convert|561|sqmi}} is land and {{convert|7.5|sqmi}} (1.3%) is water.<ref name="census-density"/>

===Climate and weather===
{{climate chart
|[[Aledo, Illinois]]
|11|29|1.27
|17|35|1.29
|26|47|2.43
|37|61|3.69
|48|72|3.92
|59|81|4.43
|62|84|4.21
|60|82|4.28
|51|75|3.31
|40|64|2.73
|28|47|2.50
|17|34|1.92
|float=right
|units=imperial
|clear=both
|source=The Weather Channel<ref name="weather">{{cite web
  |url=http://www.weather.com/weather/wxclimatology/monthly/graph/USIL0011
  |title=Monthly Averages for Aledo, Illinois
  |access-date=January 27, 2011
  |publisher=The Weather Channel
}}</ref>}}
In recent years, average temperatures in the county seat of Aledo have ranged from a low of {{convert|11|°F}} in January to a high of {{convert|84|°F}} in July, although a record low of {{convert|-30|°F}} was recorded in February 1905 and a record high of {{convert|113|°F}} was recorded in July 1936. Average monthly precipitation ranged from {{convert|1.27|in}} in January to {{convert|4.43|in}} in June.<ref name="weather"/>

===Major highways===
* [[Image:US 67.svg|20px]] [[U.S. Highway 67]]
* [[Image:Illinois 17.svg|20px]] [[Illinois Route 17]]
* [[Image:Illinois 94.svg|20px]] [[Illinois Route 94]]
* [[Image:Illinois 135.svg|20px]] [[Illinois Route 135]]

===Adjacent counties===
* [[Rock Island County, Illinois|Rock Island County]] - north
* [[Henry County, Illinois|Henry County]] - east
* [[Knox County, Illinois|Knox County]] - southeast
* [[Henderson County, Illinois|Henderson County]] - south
* [[Warren County, Illinois|Warren County]] - south
* [[Des Moines County, Iowa|Des Moines County]], [[Iowa]] - southwest
* [[Louisa County, Iowa|Louisa County]], [[Iowa]] - west

==Demographics==
{{US Census population
|1830= 26
|1840= 2352
|1850= 5246
|1860= 15042
|1870= 18769
|1880= 19502
|1890= 18545
|1900= 20945
|1910= 19723
|1920= 18800
|1930= 16641
|1940= 17701
|1950= 17374
|1960= 17149
|1970= 17294
|1980= 19286
|1990= 17290
|2000= 16957
|2010= 16434
|2020 = 15699
|estyear=2023
|estimate=15487
|estref=<ref name="USCensusEst2023">{{cite web|url=https://www.census.gov/programs-surveys/popest/data/tables.html|title=Annual Estimates of the Resident Population for Counties: April 1, 2020 to July 1, 2023|publisher=United States Census Bureau|access-date=April 2, 2024}}</ref>
|align-fn=center
|footnote=U.S. Decennial Census<ref>{{cite web|url=https://www.census.gov/programs-surveys/decennial-census.html|title=U.S. Decennial Census|publisher=United States Census Bureau|access-date=July 7, 2014}}</ref><br />1790-1960<ref>{{cite web|url=http://mapserver.lib.virginia.edu|title=Historical Census Browser|publisher=University of Virginia Library|access-date=July 7, 2014}}</ref> 1900-1990<ref>{{cite web|url=https://www.census.gov/population/cencounts/il190090.txt|title=Population of Counties by Decennial Census: 1900 to 1990|publisher=United States Census Bureau|access-date=July 7, 2014}}</ref><br />1990-2000<ref>{{cite web|url=https://www.census.gov/population/www/cen2000/briefs/phc-t4/tables/tab02.pdf|title=Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000|publisher=United States Census Bureau|access-date=July 7, 2014}}</ref> 2010<ref name="QF">{{cite web|title=QuickFacts |url = https://www.census.gov/quickfacts/fact/table/mercercountyillinois/PST045221 |publisher=[[United States Census Bureau]] |access-date=January 23, 2021 }}</ref>
}}

===2020 census===
{| class="wikitable sortable" style="text-align:center;"
|+'''Mercer County, Illinois – Racial and ethnic composition'''<br><small>{{nobold|''Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos may be of any race.''}}</small>
!Race / Ethnicity <small>(''NH = Non-Hispanic'')</small>
!Pop 1980<ref name=1980Census>{{Cite web|title=1980 Census of Population - General Population Characteristics - Illinois- Table 14 - Persons by Race and Table 16 (p. 18-28) - Total Persons and Spanish Origin Persons by Type of Spanish Origin and Race (p. 29-39)|url=https://www2.census.gov/prod2/decennial/documents/1980a_ilAB-03.pdf|website=[[United States Census Bureau]]|page=}}</ref>
!Pop 1990<ref name=1990Census>{{Cite web|title=1990 Census of Population - General Population Characteristics - Illinois - Table 6 - Race and Hispanic Orogin|url=https://www2.census.gov/library/publications/decennial/1990/cp-2/cp-2-15-1.pdf|website=[[United States Census Bureau]]}}</ref>
!Pop 2000<ref name=2000CensusP004>{{Cite web|title=P004: Hispanic or Latino, and Not Hispanic or Latino by Race – 2000: DEC Summary File 1 – Mercer County, Illinois|url=https://data.census.gov/table?g=050XX00US17131&tid=DECENNIALSF12000.P004|website=[[United States Census Bureau]] |access-date= }}</ref>
!Pop 2010<ref name=2010CensusP2>{{Cite web|title=P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2010: DEC Redistricting Data (PL 94-171) – Mercer County, Illinois|url=https://data.census.gov/cedsci/table?q=p2&g=050XX00US17131&tid=DECENNIALPL2010.P2|website=[[United States Census Bureau]] |access-date= }}</ref>
!style="background-color: #ffffb3;" | Pop 2020<ref name=2020CensusP2>{{Cite web|title=P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2020: DEC Redistricting Data (PL 94-171) – Mercer County, Illinois|url=https://data.census.gov/cedsci/table?q=p2&g=050XX00US17131&tid=DECENNIALPL2020.P2|website=[[United States Census Bureau]] |access-date= }}</ref>
!% 1980
!% 1990
!% 2000
!% 2010
!style="background-color: #ffffb3;" |% 2020
|-
|[[Non-Hispanic or Latino whites|White]] alone (NH)
|19,096
|17,082
|16,551
|15,912
|style='background: #ffffe6; |14,578
|99.01%
|98.80%
|97.61%
|96.82%
|style='background: #ffffe6; |92.86%
|-
|[[Non-Hispanic or Latino African Americans|Black or African American]] alone (NH)
|23
|30
|48
|46
|style='background: #ffffe6; |68
|0.12%
|0.17%
|0.28%
|0.28%
|style='background: #ffffe6; |0.43%
|-
|[[Native Americans in the United States|Native American]] or [[Alaska Native]] alone (NH)
|14
|33
|18
|15
|style='background: #ffffe6; |26
|0.07%
|0.19%
|0.11%
|0.09%
|style='background: #ffffe6; |0.17%
|-
|[[Asian Americans|Asian]] alone (NH)
|19
|35
|29
|51
|style='background: #ffffe6; |37
|0.10%
|0.20%
|0.17%
|0.31%
|style='background: #ffffe6; |0.24%
|-
|[[Native Hawaiian]] or [[Pacific Islander Americans|Pacific Islander]] alone (NH)
|x <ref>included in the Asian category in the 1980 Census</ref>
|x <ref>included in the Asian category in the 1990 Census</ref>
|1
|1
|style='background: #ffffe6; |2
|x
|x
|0.01%
|0.01%
|style='background: #ffffe6; |0.01%
|-
|[[Race and ethnicity in the United States census|Other race]] alone (NH)
|19
|1
|5
|6
|style='background: #ffffe6; |17
|0.10%
|0.01%
|0.03%
|0.04%
|style='background: #ffffe6; |0.11%
|-
|[[Multiracial Americans|Mixed race or Multiracial]] (NH)
|x <ref>not an option in the 1980 Census</ref>
|x <ref>not an option in the 1990 Census</ref>
|89
|96
|style='background: #ffffe6; |503
|x
|x
|0.52%
|0.58%
|style='background: #ffffe6; |3.20%
|-
|[[Hispanic and Latino Americans|Hispanic or Latino]] (any race)
|115
|109
|216
|307
|style='background: #ffffe6; |468
|0.60%
|0.63%
|1.27%
|1.87%
|style='background: #ffffe6; |2.98%
|-
|'''Total'''
|'''19,286'''
|'''17,290'''
|'''16,957'''
|'''16,434'''
|style='background: #ffffe6; |'''15,699 '''
|'''100.00%'''
|'''100.00%'''
|'''100.00%'''
|'''100.00%'''
|style='background: #ffffe6; |'''100.00%'''
|}

===2010 census===
As of the [[2010 United States census]], there were 16,434&nbsp;people, 6,734&nbsp;households, and 4,724&nbsp;families residing in the county.<ref name="census-dp1">{{cite web
  |url=http://factfinder.census.gov/bkmk/table/1.0/en/DEC/10_DP/DPDP1/0500000US17131
  |title=DP-1 Profile of General Population and Housing Characteristics: 2010 Demographic Profile Data
  |access-date=July 12, 2015
  |publisher=[[United States Census Bureau]]
  |archive-url=https://archive.today/20200213034214/http://factfinder.census.gov/bkmk/table/1.0/en/DEC/10_DP/DPDP1/0500000US17131
  |archive-date=February 13, 2020
|url-status=dead
  }}</ref> The population density was {{convert|29.3|PD/sqmi}}. There were 7,358 housing units at an average density of {{convert|13.1|/sqmi}}.<ref name="census-density">{{cite web
  |url=http://factfinder.census.gov/bkmk/table/1.0/en/DEC/10_SF1/GCTPH1.CY10/0500000US17131
  |access-date=July 12, 2015
  |title=Population, Housing Units, Area, and Density: 2010 - County
  |publisher=[[United States Census Bureau]]
  |archive-url=https://archive.today/20200212200156/http://factfinder.census.gov/bkmk/table/1.0/en/DEC/10_SF1/GCTPH1.CY10/0500000US17131
  |archive-date=February 12, 2020
|url-status=dead
  }}</ref> The racial makeup of the county was 98.3% white, 0.3% black or African American, 0.3% Asian, 0.1% American Indian, 0.3% from other races, and 0.7% from two or more races. Those of Hispanic or Latino origin made up 1.9% of the population.<ref name="census-dp1"/> In terms of ancestry, 25.9% were [[Germans|German]], 18.2% were [[Irish people|Irish]], 11.3% were [[English people|English]], 9.4% were [[Swedes|Swedish]], and 7.4% were [[Americans|American]].<ref name="census-dp2">{{cite web
  |url=http://factfinder.census.gov/bkmk/table/1.0/en/ACS/10_5YR/DP02/0500000US17131
  |title=DP02 SELECTED SOCIAL CHARACTERISTICS IN THE UNITED STATES – 2006-2010 American Community Survey 5-Year Estimates
  |access-date=July 12, 2015
  |publisher=[[United States Census Bureau]]
  |archive-url=https://archive.today/20200213032119/http://factfinder.census.gov/bkmk/table/1.0/en/ACS/10_5YR/DP02/0500000US17131
  |archive-date=February 13, 2020
|url-status=dead
  }}</ref>

Of the 6,734&nbsp;households, 30.1% had children under the age of 18 living with them, 58.3% were married couples living together, 7.9% had a female householder with no husband present, 29.8% were non-families, and 25.8% of all households were made up of individuals. The average household size was 2.41 and the average family size was 2.88. The median age was 43.7 years.<ref name="census-dp1"/>

The median income for a household in the county was $50,909 and the median income for a family was $62,025. Males had a median income of $46,136 versus $30,392 for females. The per capita income for the county was $25,332. About 8.2% of families and 9.3% of the population were below the [[poverty line]], including 14.9% of those under age 18 and 7.2% of those age 65 or over.<ref name="census-dp3">{{cite web
  |url=http://factfinder.census.gov/bkmk/table/1.0/en/ACS/10_5YR/DP03/0500000US17131
  |title=DP03 SELECTED ECONOMIC CHARACTERISTICS – 2006-2010 American Community Survey 5-Year Estimates
  |access-date=July 12, 2015
  |publisher=[[United States Census Bureau]]
  |archive-url=https://archive.today/20200213033028/http://factfinder.census.gov/bkmk/table/1.0/en/ACS/10_5YR/DP03/0500000US17131
  |archive-date=February 13, 2020
|url-status=dead
  }}</ref>

==Communities==

===Cities===
* [[Aledo, Illinois|Aledo]]
* [[Keithsburg, Illinois|Keithsburg]]
* [[New Boston, Illinois|New Boston]]

===Villages===
{{div col|colwidth=22em}}
* [[Alexis, Illinois|Alexis]]
* [[Joy, Illinois|Joy]]
* [[Matherville, Illinois|Matherville]]
* [[North Henderson, Illinois|North Henderson]]
* [[Reynolds, Illinois|Reynolds]]   (Part in Rock Island County)
* [[Seaton, Illinois|Seaton]]
* [[Sherrard, Illinois|Sherrard]]
* [[Viola, Illinois|Viola]]
* [[Windsor, Mercer County, Illinois|Windsor]]
{{div col end}}

=== Census-designated place ===
{{div col|colwidth=22em}}
* [[Cable, Illinois|Cable]]
* [[Eliza, Illinois|Eliza]]
* [[Hamlet, Illinois|Hamlet]]
* [[Millersburg, Illinois|Millersburg]]
* [[Preemption, Illinois|Preemption]]
* [[Swedona, Illinois|Swedona]]
{{div col end}}

===Unincorporated communities===
{{div col|colwidth=22em}}
* [[Boden, Illinois|Boden]]
* [[Burgess, Illinois|Burgess]]
* [[Gilchrist, Mercer County, Illinois|Gilchrist]]
* [[Mannon, Illinois|Mannon]]
* [[Marston, Illinois|Marston]]
* [[Petersville, Illinois|Petersville]]
* [[Shale City, Illinois|Shale City]]
* [[Sunbeam, Illinois|Sunbeam]]
* [[Wanlock, Illinois|Wanlock]]
{{div col end}}

===Townships===
Mercer County is divided into fifteen [[Township (United States)|townships]]:

{{div col|colwidth=22em}}
* [[Abington Township, Mercer County, Illinois|Abington]]
* [[Duncan Township, Mercer County, Illinois|Duncan]]
* [[Eliza Township, Mercer County, Illinois|Eliza]]
* [[Greene Township, Mercer County, Illinois|Greene]]
* [[Keithsburg Township, Mercer County, Illinois|Keithsburg]]
* [[Mercer Township, Mercer County, Illinois|Mercer]]
* [[Millersburg Township, Mercer County, Illinois|Millersburg]]
* [[New Boston Township, Mercer County, Illinois|New Boston]]
* [[North Henderson Township, Mercer County, Illinois|North Henderson]]
* [[Ohio Grove Township, Mercer County, Illinois|Ohio Grove]]
* [[Perryton Township, Mercer County, Illinois|Perryton]]
* [[Preemption Township, Mercer County, Illinois|Preemption]]
* [[Richland Grove Township, Mercer County, Illinois|Richland Grove]]
* [[Rivoli Township, Mercer County, Illinois|Rivoli]]
* [[Suez Township, Mercer County, Illinois|Suez]]
{{div col end}}

==Politics==
{{Unreferenced section|date=December 2019}}
Historically, Mercer County was a solidly Republican Yankee-influenced county, and before the Republican Party existed a stronghold of the [[Whig Party (United States)|Whig Party]]. The county never voted for a Democratic presidential candidate until [[Lyndon Johnson]]’s 1964 landslide over [[Barry Goldwater]] – the solitary break in Whig and Republican dominance occurring in 1912 when the GOP was mortally split and [[Progressive Party (United States, 1912)|Progressive]] [[Theodore Roosevelt]] carried the county over conservative incumbent President [[William Howard Taft]]. After Johnson’s victory in the county, Mercer voted to being Republican between 1968 and 1984, but [[Ronald Reagan|Reagan]]’s landslide in that election saw a swing to the Democrats that was capitalized upon by [[Michael Dukakis]] to carry the county in 1988. Between then and 2012, Mercer was solidly Democratic, but concern over declining economic opportunities in the “[[Rust Belt]]” caused a dramatic swing to populist Republican [[Donald Trump]] in 2016. Trump’s performance was the best by a Republican since [[Richard Nixon|Richard Nixon's]] 3,000-plus-county landslide in 1972.

Mercer County is located in [[Illinois's 17th congressional district|Illinois's 17th Congressional District]] and is currently represented by Democrat [[Cheri Bustos]]. Within the [[Illinois House of Representatives]], the county is located in the 74th district and is currently represented by Republican [[Daniel Swanson]]. The county is located in the 37th district of the [[Illinois Senate]], and is currently represented by Republican [[Chuck Weaver]].

{{PresHead|place=Mercer County, Illinois|source=<ref>{{Cite web|url=http://uselectionatlas.org/RESULTS|title=Dave Leip's Atlas of U.S. Presidential Elections|last=Leip|first=David|website=uselectionatlas.org|access-date=November 11, 2018}}</ref>}}
<!-- PresRow should be {{PresRow|Year|Winning party|GOP vote #|Dem vote #|3rd party vote #|State}} -->
{{PresRow|1892|Republican|2,470|1,975|242|Illinois}}
{{PresRow|1896|Republican|3,120|2,329|75|Illinois}}
{{PresRow|1900|Republican|3,304|2,110|149|Illinois}}
{{PresRow|1904|Republican|3,230|1,386|459|Illinois}}
{{PresRow|1908|Republican|2,871|1,777|344|Illinois}}
{{PresRow|1912|Progressive|959|1,602|2,435|Illinois}}
{{PresRow|1916|Republican|5,308|3,430|270|Illinois}}
{{PresRow|1920|Republican|5,531|1,574|311|Illinois}}
{{PresRow|1924|Republican|5,618|1,699|908|Illinois}}
{{PresRow|1928|Republican|5,699|2,316|58|Illinois}}
{{PresRow|1932|Republican|4,436|4,309|90|Illinois}}
{{PresRow|1936|Republican|5,028|4,751|105|Illinois}}
{{PresRow|1940|Republican|6,336|3,830|38|Illinois}}
{{PresRow|1944|Republican|5,667|3,277|34|Illinois}}
{{PresRow|1948|Republican|5,267|3,117|36|Illinois}}
{{PresRow|1952|Republican|6,416|2,679|2|Illinois}}
{{PresRow|1956|Republican|5,732|2,969|7|Illinois}}
{{PresRow|1960|Republican|5,582|3,476|3|Illinois}}
{{PresRow|1964|Democratic|4,220|4,410|0|Illinois}}
{{PresRow|1968|Republican|4,844|3,143|613|Illinois}}
{{PresRow|1972|Republican|5,452|3,477|11|Illinois}}
{{PresRow|1976|Republican|4,816|4,090|76|Illinois}}
{{PresRow|1980|Republican|5,144|3,361|651|Illinois}}
{{PresRow|1984|Republican|4,907|3,982|38|Illinois}}
{{PresRow|1988|Democratic|3,683|4,204|42|Illinois}}
{{PresRow|1992|Democratic|2,983|3,990|1,567|Illinois}}
{{PresRow|1996|Democratic|2,688|4,278|931|Illinois}}
{{PresRow|2000|Democratic|3,688|4,400|230|Illinois}}
{{PresRow|2004|Democratic|4,405|4,512|57|Illinois}}
{{PresRow|2008|Democratic|3,833|4,887|150|Illinois}}
{{PresRow|2012|Democratic|3,876|4,507|185|Illinois}}
{{PresRow|2016|Republican|4,807|3,071|647|Illinois}}
{{PresRow|2020|Republican|5,418|3,280|216|Illinois}}
{{PresRow|2024|Republican|5,215|2,950|208|Illinois}}
{{PresFoot}}

==See also==
* [[National Register of Historic Places listings in Mercer County, Illinois]]

==Footnotes==
{{Reflist|2}}

==Further reading==
* William C. Ives, "Abraham Lincoln in Mercer County, Illinois, 1832, 1834, 1858," ''Journal of the Illinois State Historical Society,'' vol. 101 (Fall–Winter 2008), pp.&nbsp;329–347.
* [https://archive.org/details/historyofmercerh00merc ''History of Mercer and Henderson Counties, Together with Biographical Matter, Statistics, Etc.''] Chicago: H.H. Hill and Company, 1882.

==External links==
* {{Official website|http://www.mercercountyil.org/}}
* [http://www.illinoisancestors.org/mercer/index.htm Illinois Ancestors Mercer County]

{{Geographic Location
|Centre    = Mercer County, Illinois
|North     = [[Rock Island County, Illinois|Rock Island County]]
|Northeast =
|East      = [[Henry County, Illinois|Henry County]]
|Southeast = [[Knox County, Illinois|Knox County]]
|South     = [[Henderson County, Illinois|Henderson County]] and [[Warren County, Illinois|Warren County]]
|Southwest = [[Des Moines County, Iowa]]
|West      = [[Louisa County, Iowa]]
|Northwest =
}}
{{Mercer County, Illinois}}
{{Quad Cities}}
{{Illinois}}
{{Authority control}}
{{Coord|41.20|-90.74|display=title|type:adm2nd_region:US-IL_source:UScensus1990}}

[[Category:Mercer County, Illinois| ]]
[[Category:Illinois counties]]
[[Category:1825 establishments in Illinois]]
[[Category:Illinois counties on the Mississippi River]]
[[Category:Populated places established in 1825]]
[[Category:Quad Cities]]