View source for Mackinac Bridge

{{Short description|Suspension bridge in Michigan, US}}
{{Use American English|date = December 2019}}
{{Use mdy dates|date=March 2024}}
{{Infobox bridge
| bridge_name = Mackinac Bridge
| image = Mackinac Bridge 2022.jpg
| image_upright = 1.2
| caption = Mackinac Bridge in October 2022
| official_name = 
| also_known_as = ''Mighty Mac'' or ''Big Mac''
| carries = 4 lanes of {{jct|state=MI|I|75|Tour|GLCT}}
| crosses = [[Straits of Mackinac]]
| locale = [[St. Ignace, Michigan|St. Ignace]] and [[Mackinaw City, Michigan|Mackinaw City]], Michigan
| maint = [[Mackinac Bridge Authority]]
| id = 
| design = [[Suspension bridge]]
| designer = [[David B. Steinman]]
| mainspan = {{convert|3800|ft|m|0|abbr=on}}<ref name=structurae />
| length = {{convert|26372|ft|m|0|abbr=on}}<ref name=mbafacts>{{cite web |author = Mackinac Bridge Authority |author-link = Mackinac Bridge Authority |date = n.d. |title = Facts & Figures |url = https://www.mackinacbridge.org/history/facts-figures/ |publisher = Mackinac Bridge Authority |access-date = January 22, 2018 |archive-url = https://web.archive.org/web/20180122011707/https://www.mackinacbridge.org/history/facts-figures/ |archive-date = January 22, 2018 |url-status = dead }}</ref>
| width = {{convert|68.6|ft|1|abbr=on}} (total width)<ref name=structurae /><br />{{convert|54|ft|m|abbr=on}} (road width)<br />{{convert|38.1|ft|abbr=on}} (depth)<ref name=structurae>{{Structurae|id=20000141 |title=Mackinac Straits Bridge |access-date=January 30, 2010}}</ref>
| height = {{convert|552|ft|m|0|abbr=on}} (tower height);<ref name=structurae /> {{convert|200|ft|m|0|abbr=on}} (deck height)<ref name="mbafacts"/>
| clearance = <!-- from roadway surface (deck) to bottom of lower arch in suspension towers - figure not found, yet -->
| below = {{convert|155|ft|m|0|abbr=on}}<ref name="mbafacts"/>
| traffic = 11,600
| open = {{start date and age|1957|11|01}}
| closed = 
| toll = $2.00 per axle for passenger vehicles ($4.00 per car). $5.00 per axle for motor homes, and commercial vehicles.<ref name="mba-fares">{{cite web |author = Mackinac Bridge Authority |url = https://www.mackinacbridge.org/fare-schedule-9/ |title = Mackinac Bridge Fare Schedules |publisher = Mackinac Bridge Authority |year = 2010 |access-date = January 30, 2010 |archive-url = https://web.archive.org/web/20091222183944/https://www.mackinacbridge.org/fare-schedule-9/ |archive-date = December 22, 2009 |url-status = dead }}</ref>
| coordinates = {{Coord|45.817059|-84.727822|region:US-MI_type:landmark_scale:50000|display=inline,title}}
}}

The '''Mackinac Bridge''' ({{IPAc-en|ˈ|m|æ|k|ə|n|ɔː}} {{respell|MAK|ə|naw}}; also referred to as the '''Mighty Mac''' or '''Big Mac''')<ref>{{cite web |year = 2017 |title = 'Mighty Mac' Bridge Run |url = https://www.saintignace.org/event/mighty-mac-bridge-race/ |access-date = September 8, 2017 |publisher = St. Ignace Chamber of Commerce }}</ref> is a [[suspension bridge]] that connects the [[Upper Peninsula of Michigan|Upper]] and [[Lower Peninsula of Michigan|Lower]] peninsulas of the U.S. state of [[Michigan]]. It spans the [[Straits of Mackinac]], a body of water connecting [[Lake Michigan]] and [[Lake Huron]], two of the [[Great Lakes]]. Opened in 1957, the {{convert|26372|ft|mi km|adj=mid|-long|sigfig=4}}<ref name=mbafacts/> bridge is the world's [[List of longest suspension bridge spans|29th-longest main span]] and is the longest suspension bridge between anchorages in the Western Hemisphere.<ref name=mba-about /> The Mackinac Bridge is part of [[Interstate 75 in Michigan|Interstate&nbsp;75]] (I-75) and carries the Lake Michigan and Huron components of the [[Great Lakes Circle Tour]] across the straits; it is also a segment of the U.S. [[North Country Trail|North Country National Scenic Trail]]. The bridge connects the city of [[St. Ignace, Michigan|St. Ignace]] to the north with the village of [[Mackinaw City, Michigan|Mackinaw City]] to the south.

Envisioned since the 1880s, the bridge was designed by the engineer [[David B. Steinman]] and completed in 1957 only after many decades of struggles to begin construction.<ref>{{cite web |author = Mackinac Bridge Authority |date = n.d. |title = History of the Bridge, Mackinac Bridge |url = https://www.mackinacbridge.org/history/history-of-the-bridge/ |access-date = June 10, 2023 |publisher = Mackinac Bridge Authority |language = en }}</ref> The bridge has since become an iconic symbol of the state of Michigan.<ref>{{cite news |title = The Mackinac Bridge turns 60 and still looks good: How long can it last? |url = https://www.freep.com/story/news/local/michigan/2017/10/29/mackinac-bridge-turning-60-and-still-looking-good-how-long-can-last/804222001/ |access-date = March 28, 2024 |first = Keith |last = Matheny |newspaper = [[Detroit Free Press]] |date = October 29, 2017 |language = en-US }}</ref><ref>{{cite web |title = Light The Mackinac Bridge |url = https://www.mackinawinfo.com/lightthebridge/ |access-date = June 10, 2023 |website = Mackinaw City & Mackinac Island Reviews, Comments & Attractions |language = en |archive-date = June 10, 2023 |archive-url = https://web.archive.org/web/20230610194800/https://www.mackinawinfo.com/lightthebridge/ |url-status = dead }}</ref><ref>{{cite press release |title = Governor Granholm Signs Legislation Codifying Mackinac Bridge Agreement |url = https://www.michigan.gov/formergovernors/recent/granholm/press-releases/2005/12/28/granholm-signs-legislation-codifying-mackinac-bridge-agreement |date = December 28, 2005 |access-date = March 28, 2024 |publisher = Office of the Governor |language = en }}</ref>

==Length==
The bridge opened on November 1, 1957,<ref>{{cite book |title = Mighty Mac: The Official Picture History of the Mackinac Bridge |url = https://archive.org/details/mightymacofficia0000rubi |url-access = registration |first = Lawrence |last = Rubin |publisher = Wayne State University Press |year = 1958 |isbn = 978-0-814-31817-1 |page = [https://archive.org/details/mightymacofficia0000rubi/page/14 14] }}</ref> connecting two peninsulas linked for decades by ferries. At the time, the bridge was formally dedicated as the "world's longest suspension bridge between anchorages", allowing a superlative comparison to the [[Golden Gate Bridge]], which has a longer center span between towers, and the [[San Francisco–Oakland Bay Bridge]], which has an anchorage in the middle.

It remains the longest suspension bridge with two towers between anchorages in the [[Western Hemisphere]].<ref name="mba-about">{{cite web |author = Mackinac Bridge Authority |date = n.d. |url = https://mackinacbridge.org/about-the-bridge-8/ |title = About the Bridge |publisher = Mackinac Bridge Authority |access-date = January 30, 2010 |url-status = dead |archive-url = https://web.archive.org/web/20091222184021/https://www.mackinacbridge.org/about-the-bridge-8/ |archive-date = December 22, 2009 }}</ref> Much longer anchorage-to-anchorage spans have been built in the [[Eastern Hemisphere]], including the [[Akashi Kaikyō Bridge]] in Japan ({{convert|6532|ft|m|disp=or|abbr=on}}), but the long leadups to the anchorages on the Mackinac make its total shoreline-to-shoreline length of 26,372 feet<ref name="twenty-eight">{{cite web |author = Mackinac Bridge Authority |date = n.d. |url = https://www.mackinacbridge.org/history/the-mighty-mac/ |title = The Mighty Mac |publisher = Mackinac Bridge Authority }}</ref>—{{convert|28|ft|m}} short of {{convert|5|mi|km|spell=in}}—longer than the Akashi Kaikyo ({{convert|2.4|mi|km|disp=or|abbr=on}}).

The length of the bridge's main span is {{convert|3800|ft|m|0}}, which makes it the third-longest suspension span in the [[United States]] and 29th [[List of longest suspension bridge spans|longest suspension span worldwide]]. It is also [[List of longest bridges in the world|one of the world's longest bridges overall]].

==History==

===Early history===
[[File:'Vacationland', newest and largest car ferry added to Straits of Mackinaw fleet.jpg|thumb|''[[Vacationland (ferry)|Vacationland]]'', the largest and last [[Michigan State Highway Department]] [[Roll-on/roll-off|automobile ferry]] put in service prior to the completion of the Mackinac Bridge]]

The [[Algonquian peoples]] who lived in the straits area prior to the arrival of Europeans in the 17th century called this region ''[[Michilimackinac]]'', which is widely understood to mean ''Place of the Great Turtle.''<ref>{{cite web |title = History: Mackinac Island |date = May 15, 2023 |url = https://www.mackinacisland.org/blog/countdown-to-2020-a-look-at-mackinac-history-through-the-centuries/ |access-date = February 9, 2024 |publisher = Mackinac Island Tourism Bureau |language = en-US }}</ref> This is thought to refer to the shape of what is now called [[Mackinac Island]]. This interpretation of the word is debated by scholars. Trading posts at the Straits of Mackinac attracted peak populations during the summer trading season; they also developed as intertribal meeting places.<ref>{{cite web |url = https://www.michilimackinac.com/ |title = Mackinaw, Mackinac Straits, Mackinac Island |website = Michilimackinac |access-date = November 2, 2013 |archive-url = https://web.archive.org/web/20130925185840/https://www.michilimackinac.com/ |archive-date = September 25, 2013 |url-status = dead }}</ref>

As usage of the state's [[mineral]] and [[timber]] resources increased during the 19th century, the area became an important [[transport hub]]. In 1881 the three railroads that reached the Straits, the [[Michigan Central Railroad|Michigan Central]], [[Grand Rapids and Indiana Railroad|Grand Rapids & Indiana]], and the [[Detroit, Mackinac and Marquette Railroad|Detroit, Mackinac & Marquette]], jointly established the [[Mackinac Transportation Company]] to operate a [[Train ferry|railroad car ferry]] service across the straits and connect the two peninsulas.<ref>{{cite web |url = https://www.michigan.gov/mdot/0,4616,7-151-9620_11154_11188-26923--,00.html |title = I-75 / Straits of Mackinac |website = Michigan's Historic Bridges |publisher = Michigan Department of Transportation |access-date = November 2, 2013 }}</ref>

Improved [[highway]]s along the eastern shores of the [[Lower Peninsula]] brought increased automobile traffic to the Straits region starting in the 1910s. The state of Michigan initiated an automobile ferry service between Mackinaw City and St. Ignace in 1923; it eventually operated nine ferry boats that would carry as many as 9,000 vehicles per day. Traffic backups could stretch as long as {{convert|16|mi|km}}.<ref>{{cite web |url = https://www.asce.org/about-civil-engineering/history-and-heritage/historic-landmarks/mackinac-bridge |title = Mackinac Bridge |author = American Society of Civil Engineers |publisher = American Society of Civil Engineers |access-date = January 29, 2022 }}</ref>

===Plans for the bridge===
[[File:Traffic at opening of Mackinac Bridge, November 1, 1957.jpg|thumb|Bridge's opening on November 1, 1957]]
After the opening of the [[Brooklyn Bridge]] in 1883, local residents began to imagine that such a structure could span the straits. In 1884, a store owner in [[St. Ignace, Michigan|St. Ignace]] published a newspaper advertisement that included a reprint of an artist's conception of the Brooklyn Bridge with the caption "Proposed bridge across the Straits of Mackinac".<ref name="michigan1">{{cite web |url = https://www.michigan.gov/mdot/0,4616,7-151-9618_11016-25527--,00.html |title = History |publisher = Michigan Department of Transportation |access-date = November 2, 2013 }}</ref>

The idea of the bridge was discussed in the Michigan Legislature as early as the 1880s. At the time, the Straits of Mackinac area was becoming a popular tourist destination, especially following the creation of [[Mackinac National Park]] on Mackinac Island in 1875.<ref>{{cite journal |last = Widder |first = Keith |year = 1975 |title = Mackinac National Park 1875-1895 |journal = Reports in Mackinac History and Archaeology |number = 4 |publisher = Mackinac Island State Park Commission |url = https://npshistory.com/publications/mha-rpt-4.pdf |access-date = December 11, 2023 |archive-date = October 19, 2022 |archive-url = https://web.archive.org/web/20221019214524/http://npshistory.com/publications/mha-rpt-4.pdf |url-status = dead }}</ref>

At a July 1888 meeting of the board of directors of the [[Grand Hotel (Mackinac Island)|Grand Hotel]] on Mackinac Island, [[Cornelius Vanderbilt II]] proposed that a bridge be built across the straits, of a design similar to the one then under construction across the [[Firth of Forth]] in [[Scotland]]. This would advance commerce in the region and help lengthen the resort season of the hotel.<ref name="michigan1"/>

Decades went by with no formal action. In 1920, the Michigan state highway commissioner advocated construction of a floating tunnel across the Straits. At the invitation of the state legislature, C. E. Fowler of [[New York City]] put forth a plan for a long series of causeways and bridges across the straits from [[Cheboygan, Michigan|Cheboygan]], {{convert|17|mi|km}} southeast of Mackinaw City, to St. Ignace, using [[Bois Blanc Island (Michigan)|Bois Blanc]], [[Round Island (Michigan)|Round]], and Mackinac islands as intermediate steps.<ref>{{cite web |author = Mackinac Bridge Authority |date = n.d. |title = History of the Bridge, Mackinac Bridge |url = https://www.mackinacbridge.org/history/history-of-the-bridge/ |access-date = October 19, 2022 |publisher = Mackinac Bridge Authority |language = en }}</ref>

===Formal planning===
In 1923, the state legislature ordered the State Highway Department to establish ferry service across the strait. More and more people used ferries to cross the straits each year, and as they did, the movement to build a bridge increased. [[Chase Osborn]], a former governor, wrote:

{{blockquote|Michigan is unifying itself, and a magnificent new route through Michigan to Lake Superior and the Northwest United States is developing, via the Straits of Mackinac. It cannot continue to grow as it ought with clumsy and inadequate ferries for any portion of the year.<ref>{{harvp|Rubin|1958|p=13}}.</ref>}}

By 1928, the ferry service had become so popular and so expensive to operate that Governor [[Fred W. Green]] ordered the department to study the feasibility of building a bridge across the strait. The department deemed the idea feasible, estimating the cost at $30&nbsp;million (equivalent to ${{formatprice|{{Inflation|US-GDP|30000000|1928}}}} in {{Inflation-year|US-GDP}}{{Inflation-fn|US-GDP}}).

In 1934, the Michigan Legislature created the ''Mackinac Straits Bridge Authority'' to explore possible methods of constructing and funding the proposed bridge.<ref name=":0">{{cite book |author = Board of Engineers |date = January 10, 1950 |title = Proposed Mackinac Straits Bridge Preliminary Report |url = https://www.michigan.gov/-/media/Project/Websites/egle/Documents/Programs/OGMD/Catalog/12/Proposed-Prelim-Report.pdf |publisher = Mackinac Bridge Authority |access-date = June 20, 2024 }}</ref> The Legislature authorized the Authority to seek financing for the project. In the mid-1930s, during the Great Depression, when numerous infrastructure projects received federal aid, the Authority twice attempted to obtain federal funds for the project but was unsuccessful. The [[United States Army Corps of Engineers]] and President [[Franklin D. Roosevelt]] endorsed the project but Congress never appropriated funds. Between 1936 and 1940, the Authority selected a route for the bridge based on preliminary studies. Borings were made for a detailed [[geology|geological]] study of the route.<ref name=":0" />

The preliminary plans for the bridge featured a three-lane roadway, a railroad crossing on the underdeck of the span, and a center-anchorage double-suspension bridge configuration similar to the design of the San Francisco–Oakland Bay Bridge. Because this would have required sinking an anchorage pier in the deepest area of the Straits, the practicality of this design may have been questionable.{{Citation needed|date=September 2011}} A concrete causeway, approximately {{convert|4000|ft|m|0}}, extending from the northern shore, was constructed in shallow water from 1939 to 1941. However, a unique engineering challenge was created by the tremendous forces that operate against the base of the bridge, because the lakes freeze during the winter, causing large icebergs to place enormous stress on the bridge.{{citation needed|date=October 2020}}

At that time, with funding for the project still uncertain, further work was put on hold because of the outbreak of [[World War II]]. The ''Mackinac Straits Bridge Authority'' was abolished by the state legislature in 1947, but the same body created a new [[Mackinac Bridge Authority]] three years later in 1950. In June 1950, engineers were retained for the project. By then, it was reported that cars queuing for the ferry at Mackinaw City did not reach St. Ignace until five hours later, and the typical capacity of 460 vehicles per hour could not match the estimated 1,600 for a bridge.<ref>{{harvp|Rubin|1958|p=23}}.</ref>

After a report by the engineers in January 1951,<ref>{{cite book |type = Report |url = https://www.michigan.gov/documents/deq/Proposed_Prelim_Report_opt_306071_7.pdf |title = Proposed Mackinac Straits Bridge Preliminary Report |access-date = April 15, 2013 |last = Ammann |first = Othmar |author-link = Othmar Ammann |date = January 10, 1951 }}</ref> the state legislature authorized the sale of $85&nbsp;million (equivalent to ${{formatprice|{{Inflation|US-GDP|85000000|1952}}}} in {{Inflation-year|US-GDP}}{{Inflation-fn|US-GDP}}) in bonds for bridge construction on April 30, 1952. However, a weak bond market in 1953 forced a delay of more than a year before the bonds could be issued.

===Engineering and construction===
[[File:Mackinac Bridge Tower.jpg|thumb|upright|left|View of the north tower of the bridge]]
[[David B. Steinman]] was appointed as the design engineer in January 1953 and by the end of 1953, estimates and contracts had been negotiated. A civil engineer at the firm, Abul Hasnat, did the preliminary plans for the bridge. Total cost estimate at that time was $95&nbsp;million (equivalent to ${{formatprice|{{Inflation|US-GDP|95000000|1953}}}} in {{Inflation-year|US-GDP}}{{Inflation-fn|US-GDP}}) with estimated completion by November 1, 1956.  Tolls collected were to pay for the bridge in 20 years.<ref>{{cite magazine |url = https://books.google.com/books?id=8NsDAAAAMBAJ&pg=PA132 |title = Mackinac Bridge Will Rival Golden Gate |magazine = [[Popular Mechanics]] |date = August 1953 |volume = 100 |issue = 2 |page = 132 |issn = 0032-4558 |access-date = February 21, 2012 }}</ref> Construction began on May 7, 1954. The bridge was built under two major contracts. The [[Merritt-Chapman & Scott|Merritt-Chapman and Scott Corporation]] of New York was awarded the contract for all major substructure work for $25.7 million (equivalent to ${{formatprice|{{inflation|US-GDP|25700000|1953}}}} in {{inflation-year|US-GDP}}{{inflation-fn|US-GDP}}), while the [[American Bridge Company|American Bridge Division]] of [[United States Steel Corporation]] was awarded a contract of more than $44&nbsp;million (equivalent to ${{formatprice|{{Inflation|US-GDP|44000000|1954}}}} in {{Inflation-year|US-GDP}}{{Inflation-fn|US-GDP}}) to build the [[steel]] superstructure.<ref>{{cite book |last = Hyde |first = Charles K. |year = 1993 |url = https://archive.org/details/historichighwayb0000hyde |url-access = registration |title = Historic Highway Bridges of Michigan |location = Detroit |publisher = [[Wayne State University Press]] |isbn = 978-0-8143-2448-6 |page = 165 }}</ref>

Construction, staged using the 1939–1941 causeway, took three and a half years (four summers, no winter construction) at a total cost of $100 million and the lives of five workers. Contrary to popular belief, none of them are entombed in the bridge.<ref>{{cite web |author = Mackinac Bridge Authority |date = n.d. |url = https://www.mackinacbridge.org/bridge-workers-61/ |title = In Memory of: Bridge Workers |publisher = Mackinac Bridge Authority |access-date = February 21, 2012 |archive-url = https://web.archive.org/web/20120220102023/https://www.mackinacbridge.org/bridge-workers-61/ |archive-date = February 20, 2012 |url-status = dead }}</ref> It opened to traffic on schedule on November 1, 1957, and the ferry service ceased on the same day. The bridge was formally dedicated on June 25, 1958.

[[G. Mennen Williams]] was governor during the construction of the Mackinac Bridge. Williams was the first to pay the toll (then $3.25, equivalent to ${{formatnum:{{Inflation|US|3.25|1957|r=2}}}} in {{Inflation/year|US}}) to cross the bridge and rode on the ''[[Vacationland (ferry)|Vacationland]]''<nowiki/>'s last St. Ignace–Mackinaw City ferry trip about an hour later,<ref>[https://www.newspapers.com/article/the-sault-news-special-mackinac-bridge-e/154621942/ "All Roads Lead To Straits Today For Opening Of Bridge"], ''Sault Ste. Marie Evening News'', November 1, 1957, front page.</ref> and he later began the tradition of the governor leading the [[Mackinac Bridge Walk]] across it every [[Labor Day]].<ref name="nga">{{cite web |url = https://www.nga.org/portal/site/nga/menuitem.29fab9fb4add37305ddcbeeb501010a0/?vgnextoid=9dca49bc0a733010VgnVCM1000001a01010aRCRD |title = Michigan Governor Gerhard Mennen Williams |publisher = [[National Governors Association]] |access-date = January 30, 2010 |url-status = dead |archive-url = https://web.archive.org/web/20100701152001/https://www.nga.org/portal/site/nga/menuitem.29fab9fb4add37305ddcbeeb501010a0/?vgnextoid=9dca49bc0a733010VgnVCM1000001a01010aRCRD |archive-date = July 1, 2010 }}</ref> Senator [[Prentiss M. Brown]] has been called the "father of the Mackinac Bridge",<ref name="mba-pmb">{{cite web |author = Mackinac Bridge Authority |date = n.d. |url = https://www.mackinacbridge.org/prentiss-m.-brown-41/ |title = Prentiss M. Brown, 'Father of the Mackinac Bridge' |publisher = Mackinac Bridge Authority |access-date = January 30, 2010 |url-status = dead |archive-url = https://web.archive.org/web/20091222184239/https://www.mackinacbridge.org/prentiss-m.-brown-41/ |archive-date = December 22, 2009 }}</ref> and was honored with a special memorial [[token coin|bridge token]] created by the Mackinac Bridge Authority.<ref name="mba-tokens">{{cite web |author = Mackinac Bridge Authority |url = https://www.mackinacbridge.org/token-order-form-21/ |title = Mackinac Bridge commemorative token gift packs |publisher = Mackinac Bridge Authority |year = 2009 |access-date = January 30, 2010 |archive-url = https://web.archive.org/web/20091222184106/https://www.mackinacbridge.org/token-order-form-21/ |archive-date = December 22, 2009 |url-status = dead }}</ref>

The bridge officially achieved its 100&nbsp;millionth crossing exactly 40 years after its dedication, on June 25, 1998.<ref name="mbafacts"/> The 50th anniversary of the bridge's opening was celebrated on November 1, 2007, in a ceremony hosted by the Mackinac Bridge Authority at the viewing park adjacent to the St. Ignace causeway.<ref name="mbafacts"/> The bridge was designated as a [[National Historic Civil Engineering Landmark]] by the [[American Society of Civil Engineers]] in 2010.<ref>{{cite news |author = <!--Staff writer(s)/no by-line.--> |title = Mackinac Bridge Chosen as National Historic Civil Engineering Landmark |url = https://www.stignacenews.com/articles/mackinac-bridge-chosen-as-national-historic-civil-engineering-landmark/ |newspaper = [[The St. Ignace News]] |date = August 12, 2010 |access-date = February 3, 2021 }}</ref>

===History of the bridge's design===
[[File:Mackinac Bridge-2.jpg|thumb|upright|View of a bridge tower]]
{{unreferenced section|date=October 2020}}
The design of the Mackinac Bridge was directly influenced by the lessons from the [[Tacoma Narrows Bridge (1940)|first Tacoma Narrows Bridge]], which failed in 1940 because of its instability in high winds. Three years after that disaster, Steinman had published a theoretical analysis of suspension-bridge stability problems, which recommended that future bridge designs include deep stiffening [[truss]]es to support the bridge deck and an open-grid roadway to reduce its wind resistance. Both of these features were incorporated into the design of the Mackinac Bridge. The stiffening truss is open to reduce wind resistance. The road deck is shaped as an airfoil to provide lift in a cross wind, and the center two lanes are open grid to allow vertical (upward) air flow, which fairly precisely cancels the lift, making the roadway stable in design in winds of up to {{convert|150|mph|km/h}}.

==Facts and figures==
[[File:Mackinac Bridge.jpg|right|thumb|The Mackinac Bridge from the south shore]]
[[File:Mackinac Bridge at Night August 2011.jpg|right|thumb|The Mackinac Bridge at night]]
[[File:Freighter passing under Macinac Bridge.jpg|right|thumb|[[Lake freighter|Freighter]] passing under the bridge, from [[Straits State Park]]]]

The Mackinac Bridge is a [[toll bridge]] on [[Interstate 75 in Michigan|Interstate&nbsp;75]] (I-75). The [[U.S. Route 27 in Michigan|US Highway&nbsp;27]] (US&nbsp;27) designation was initially extended across the bridge.<ref name="MSHD58">{{cite MDOT map |year=1958 |section=D10}}</ref> In November 1960, sections of I-75 freeway opened from Indian River north to the southern bridge approaches in Mackinaw City,<ref name=blade1960>{{cite news |title = Michigan to Open 35 More Miles of Freeway |url = https://news.google.com/newspapers?id=2rlOAAAAIBAJ&pg=2713,1527983&dq=michigan+open+%7C+construction+interstate-75&hl=en |newspaper = [[The Blade (Toledo, Ohio)|The Blade]] |location = Toledo |agency = [[Associated Press]] |date = November 8, 1960 |page = 19 |access-date = March 22, 2013 |via = [[Google News]] }}</ref> and US&nbsp;27 was removed from the bridge.<ref name=MSHD61>{{cite MDOT map |year=1961 |section=F10 }}</ref> It is one of only three segments of I-75 that are tolled, the others being the American half of the [[Sault Ste. Marie International Bridge|International Bridge]] near [[Sault Ste. Marie, Michigan]], and [[Alligator Alley]] in [[Interstate 75 in Florida|Florida]]. The current toll is $4.00 for automobiles and $5.00 per axle for trucks. The Mackinac Bridge Authority raised the toll in 2007 to fund a $300&nbsp;million renovation program, which would include completely replacing the bridge deck.<ref name="wzzm-tolls">{{cite news |url = http://www.wzzm13.com/news/story.aspx?storyid=83364 |archive-url = https://archive.today/20130217021136/http://www.wzzm13.com/news/story.aspx?storyid=83364 |url-status = dead |archive-date = February 17, 2013 |title = Mackinac Bridge Authority Proposes Raising Tolls to Pay for Renovations |work = WZZM News |location = Walker, Michigan |publisher = [[WZZM-TV]] |date = November 7, 2007 |access-date = January 5, 2013 }}</ref>

Painting of the bridge takes seven years,<ref>{{cite web |date=December 2, 2007 |title=The Mackinac Bridge Painting Project |url=http://www.poweredbythepeople.com/painters/Michigan/Painter_Mackinaw_City.html |publisher=Michigan Painting Group}}{{Failed verification|date=April 2025}}</ref> and when painting of the bridge is complete, it begins again. The current painting project began in 1999 and was expected to take 20 years to complete because the lead-based paint needs to be removed, incurring additional disposal requirements.<ref>{{cite news |first = Brandon |last = Champion |url = http://www.mlive.com/news/grand-rapids/index.ssf/2017/03/mackinac_bridges_north_tower_t.html |title = The Mackinac Bridge Painting Project |newspaper = [[The Grand Rapids Press]] |date = March 30, 2017 }}</ref><ref>{{cite web |first = Robb |last = Westaby |url = http://fox17online.com/2013/08/05/why-painting-the-mackinac-bridge-is-taking-20-years/ |title = Why Painting The Mackinac Bridge Is Taking 20 Years |work = Fox17 Online |location = Grand Rapids, Michigan |publisher = [[WXMI-TV]] |date = August 5, 2013 }}</ref>

The bridge celebrated its 150 millionth vehicle crossing on September 6, 2009.<ref name="mba-pr">{{cite press release |url = http://www.mackinacbridge.org/index.php?action=archived&artid=192 |title = 150 Millionth Vehicle Crosses Mackinac Bridge |date = September 7, 2009 |publisher = Mackinac Bridge Authority |access-date = March 19, 2010 }}</ref>

* Length from cable bent pier to cable bent pier: {{convert|7400|ft|m|0}}.<ref name="mbafacts"/>
* Total width of the roadway: {{convert|54|ft|m|1}}<ref name="mbafacts"/>
** Two outside lanes: {{convert|12|ft|m|1}} wide each<ref name="mbafacts"/>
** Two inside lanes: {{convert|11|ft|m|1}} wide each<ref name="mbafacts"/>
** Center mall: {{convert|2|ft|m|2}}
** Catwalk, curb and rail width: {{convert|3|ft|m|2}} on each side
* Width of stiffening truss in the suspended span: {{convert|68|ft|m|1}}.<ref name="mbafacts"/>
* Depth of stiffening truss: {{convert|38.1|ft}}<ref name=structurae /><ref name="mbafacts"/>
* Height of the roadway at mid-span: approximately {{convert|200|ft|m|0}} above water level.<ref name="mbafacts"/>
* Vertical clearance at normal temperature:
** {{convert|155|ft|m|0}} at the center of the main suspension span.<ref name="mbafacts"/>
** {{convert|135|ft|m|0}} at the boundaries of the {{convert|3000|ft|m|adj=mid|-wide|sigfig=3}} navigation channel.<ref name="mbafacts"/>
* Construction cost: $99.8&nbsp;million (equivalent to ${{formatprice|{{Inflation|US-GDP|99800000|1957|r=-4}}}} in {{Inflation-year|US-GDP}}{{Inflation-fn|US-GDP}})<ref name="mbafacts"/>
* Height of towers above water: {{convert|552|ft|m|0}}<ref name="mbafacts"/>
* Max. depth of towers below water: {{convert|210|ft|m|0}}<ref name="mbafacts"/>
* Depth of water beneath the center of the bridge, {{convert|250|ft|m}}<ref name="mbafacts"/>
* Main cables:
** Number of wires in each cable: 12,580<ref name="mbafacts"/>
** Diameter of each wire: {{convert|0.196|in|cm|3}}<ref name="mbafacts"/>
** Diameter of each cable: {{convert|24.5|in|cm|2}}<ref name="mbafacts"/>
** Total length of wire in main cables: {{convert|42000|mi|km}}.<ref name="mbafacts"/>
* Total vehicle crossings, 2005: 4,236,491 (average 11,608 per day)
* Speed limit: {{convert|45|mph|km/h}} for passenger cars, {{convert|20|mph|km/h}} for heavy trucks. Heavy trucks are also required to leave a {{convert|500|ft|m|adj=on}} spacing ahead.

===Work and major accident fatalities===

Five workers died during the construction of the bridge:<ref name="mba-imo">{{cite web |author = Mackinac Bridge Authority |date = n.d. |url = http://www.mackinacbridge.org/in-memory-of-45/ |title = In Memory of |publisher = Mackinac Bridge Authority |access-date = January 30, 2010 |url-status = dead |archive-url = https://web.archive.org/web/20070912171929/http://www.mackinacbridge.org/in-memory-of-45/ |archive-date = September 12, 2007 }}</ref>
* Diver Frank Pepper ascended too quickly from a depth of {{convert|140|ft|m}} on September 16, 1954. Despite being rushed to a [[decompression chamber]], the 46-year-old died from the [[Decompression sickness|bends]].<ref>* {{cite book |last = Rubin |first = Lawrence A. |year = 1985 |url = https://books.google.com/books?id=LEh9TGZ7GToC&pg=PA77 |title = Bridging the Straits |location = Detroit |publisher = Wayne State University Press |isbn = 978-0-8143-1812-6 |pages = 135–136 }}</ref>
* 26-year-old James LeSarge lost his balance on October 10, 1954, and fell into a [[caisson (engineering)|caisson]]. He fell {{convert|40|ft|m}} and likely died of head injuries caused by impact with the criss-crossing steel beams inside the caisson.<ref name="Rubin 1985 136">{{harvp|Rubin|1985|p=136}}.</ref>
* Albert Abbott died on October 25, 1954. The forty-year-old fell {{convert|4|ft|m|spell=in}} into the water while working on an {{convert|18|in|cm|adj=on}} wide beam. Witnesses speculate he suffered a heart attack.<ref name="Rubin 1985 136"/>
* 28-year-old Jack Baker and 28-year-old Robert Koppen died in a catwalk collapse near the north tower on June 6, 1956; it was their first day on the job. Koppen's body was never recovered. Another man suffered a broken ankle.<ref>{{harvp|Rubin|1985|pp=136–138}}.</ref>
All five men are memorialized on a [[Commemorative plaque|plaque]] near the bridge's northern end (Bridge View Park). Contrary to folklore, no bodies are embedded in the concrete.<ref>{{cite magazine |magazine = [[Michigan History (magazine)|Michigan History]] |title = Michigan History |date = July–August 2007 }}</ref><ref name="mba-faq">{{cite web |author = Mackinac Bridge Authority |date = n.d. |title = Frequently Asked Questions |publisher = Mackinac Bridge Authority |url = https://www.mackinacbridge.org/history/in-memory-of/ |access-date = September 23, 2011 }}</ref>

One worker has died since the bridge was completed. Daniel Doyle fell {{convert|60|to|70|ft|m}} from scaffolding on August 7, 1997. He survived the fall but fell victim to the {{convert|50|°F|°C}} water temperature. His body was recovered the next day in {{convert|95|ft|m}} of water.

Two vehicles have fallen off the bridge:
* On September 22, 1989, Leslie Ann Pluhar died when her car, a 1987 Yugo, plunged over the {{convert|36|in|cm|adj=mid|-high}} railing. High winds were initially blamed,<ref name="zacharias">{{cite news |last = Zacharias |first = Pat |title = The Breathtaking Mackinac Bridge |newspaper = [[The Detroit News]] |date = June 6, 2000 |url = http://apps.detnews.com/apps/history/index.php?id=156 |access-date = September 11, 2010 |url-status = dead |archive-url = https://archive.today/20130121103110/http://apps.detnews.com/apps/history/index.php?id=156 |archive-date = January 21, 2013 }}</ref> which was not supported by recorded wind speed measurements taken on and around the bridge at the time of the accident.<ref>{{cite news |first = Bill |last = McGraw |date = July 8, 2007 |title = Mackinac Bridge Q&A |url = http://www.freep.com/article/20070708/NEWS06/707080577/Mackinac-Bridge-Q-A |newspaper = Detroit Free Press |access-date = January 3, 2014 |archive-date = January 3, 2014 |archive-url = https://web.archive.org/web/20140103183324/http://www.freep.com/article/20070708/NEWS06/707080577/Mackinac-Bridge-Q-A |url-status = dead }}</ref><ref>{{cite news |title = Accident Report Claims Ms. Pluhar Was Speeding |url = https://news.google.com/newspapers?nid=1988&dat=19891108&id=H4YyAAAAIBAJ&pg=3091,639880 |date = November 8, 1989 |newspaper = [[The Argus-Press]] |location = Owosso, Michigan |agency = Associated Press |page = 20 |access-date = January 3, 2014 }}</ref> Later investigation showed the driver lost control due to excessive speed and her vehicle bumped the bridge's 4-inch-high median and then crossed back through the northbound lanes, hitting a curb, jumping an outer guardrail and falling off the bridge,<ref>{{cite news |url = http://www.nysun.com/article/3232 |title = How to Build a Better Bridge |access-date = October 26, 2007 |first = David |last = Propson |date = October 14, 2004 |newspaper = [[New York Sun]] |archive-date = November 14, 2007 |archive-url = https://web.archive.org/web/20071114172349/http://www.nysun.com/article/3232 |url-status = dead }}</ref>{{Failed verification|date=November 2024}} 
* On March 2, 1997, Richard Alan Daraban drove his car, a 1996 Ford Bronco, over the edge. It was later determined to be a suicide.<ref name="daraban">{{cite court |litigants = Daraban v. State of Michigan, et al. |opinion = 223659 |court = State of Michigan Court of Appeals |date = March 15, 2002 |url = http://publicdocs.courts.mi.gov:81/opinions/final/coa/20020305_c223659(43)_223659.opn.pdf }}</ref>

On September 10, 1978, a small private plane carrying [[United States Marine Corps Reserve]] officers Maj. Virgil Osborne, Capt. James Robbins, and Capt. Wayne W. Wisbrock smashed into one of the bridge's suspension cables while flying in a heavy fog. The impact tore the wings off the plane, which then plunged into the Straits of Mackinac. All three men were killed.<ref>{{cite news |url = https://news.google.com/newspapers?nid=1988&dat=19780912&id=kWwiAAAAIBAJ&pg=5761,809952 |title = Reserve Officers Died In Mackinac Bridge Crash |newspaper = The Argus-Press |location = Owosso, Michigan |agency = Associated Press |date = September 12, 1978 |access-date = January 5, 2013 }}</ref><ref>{{harvp|Rubin|1985|pp=158–159}}.</ref>

With the exception of the annual Mackinac Bridge Walk on Labor Day, the bridge is not accessible to pedestrians. As a result, [[Suicide bridge|suicides by jumping from the bridge]] have been rare, with the most recent confirmed case taking place on December 31, 2012. No jumps have occurred during the annual bridge walks.<ref>{{cite news |first = Zac |last = Britton |date = January 2, 2013 |url = http://articles.petoskeynews.com/2013-01-02/mackinac-bridge_36117474 |title = Investigation Remains Open Following Mackinac Bridge Jump |newspaper = [[Petoskey News-Review]] |access-date = January 5, 2013 |archive-url = https://web.archive.org/web/20130105021444/http://articles.petoskeynews.com/2013-01-02/mackinac-bridge_36117474 |archive-date = January 5, 2013 |url-status = dead }}</ref> There have been roughly a dozen suicides by people jumping off the bridge {{asof|2013|lc=y}}.<ref>{{cite news |url = http://www.mlive.com/news/index.ssf/2013/01/michigan_state_police_investig_1.html |title = Michigan State Police Investigating Possible New Year's Eve suicide on the Mackinac Bridge |first = Garret |last = Ellison |date = January 1, 2013 |newspaper = Grand Rapids Press |access-date = March 28, 2024 }}</ref>

===Crossing the bridge===
Some individuals have difficulty crossing bridges, a phenomenon known as [[gephyrophobia]]. The Mackinac Bridge Authority has a Drivers Assistance Program that provides drivers for those with gephyrophobia, or anyone who is more comfortable having someone else drive them across. More than a thousand people use this service every year. Those interested can arrange, either by phone or with the toll collector, to have their cars or motorcycles driven to the other end. There is an additional fee for this service.

Bicycles and pedestrians are not permitted on the bridge. However, A program is offered to transport bicycles.<ref name="mba-bike">{{cite web |url = https://www.mackinacbridge.org/ufaqs/can-bicycle-group-get-across-mackinac-bridge/ |title = How can my bicycle group get across the Mackinac Bridge? |publisher = Mackinac Bridge Authority |date = October 24, 2016 |access-date = May 24, 2024 }}</ref> Up until 2017, an exception was allowed for riders of two annual bicycle tours.<ref name="mba-cancel">{{cite press release |url = https://www.mackinacbridge.org/2018-annual-bridge-walk-will-start-st-ignace-mackinaw-city-safety-convenience-2/#exit-off-canvas |title = 2018 Annual Bridge Walk will start in both St. Ignace and Mackinaw City for safety, convenience |publisher = Mackinac Bridge Authority |date = February 20, 2018 |access-date = March 28, 2024 }}</ref> A yearly exception is also made for pedestrians, see "Bridge Walk" below.

Travelers across the Mackinac Bridge can listen to an AM radio broadcast that recounts the history of the bridge and provides updates on driving conditions.<ref name="michiguide">{{cite web |url = http://www.michiguide.com/dials/amtis/wnhc787.html |title = WNHC787 AM 530 St. Ignace / AM 1610 Mackinaw City |website = Michiguide.com |access-date = September 20, 2008 |archive-date = August 28, 2013 |archive-url = https://web.archive.org/web/20130828183606/http://www.michiguide.com/dials/amtis/wnhc787.html |url-status = dead }}</ref>

==Bridge Walk==
[[File:Mackwalk.JPG|thumb|right|The Mackinac Bridge Walk in 2004]]
The first [[Mackinac Bridge Walk]] was held in 1958, when it was led by Governor [[G. Mennen Williams]]. The first walk was held during the Bridge's Dedication Ceremony held in late June, and has been held on Labor Day since 1959. Until 2018, school buses from local districts transported walkers from Mackinaw City to St. Ignace to begin the walk. Thousands of people, traditionally led by the governor of Michigan, cross the five-mile (8&nbsp;km) span on foot from St. Ignace to Mackinaw City. Before 1964, people walked the Bridge from Mackinaw City to St. Ignace.  Prior to 2017, two lanes of the bridge would remain open to public vehicle traffic; this policy was changed in 2017 to close the entire bridge to public vehicle traffic for the duration of the event.<ref name="mba-walk">{{cite press release |url = http://www.mackinacbridge.org/traffic-changes-announced-2017-annual-mackinac-bridge-walk/ |title = Bridge to be closed to public traffic during Annual Bridge Walk |publisher = Mackinac Bridge Authority |date = May 16, 2017 |access-date = March 28, 2024 }}</ref> The Bridge Walk is the only day of the year that hikers can hike this section of the [[North Country National Scenic Trail]].<ref name=NCTA>{{cite web |title = Michigan |url = http://northcountrytrail.org/trail/states/michigan/ |publisher = North Country Trail Association |access-date = July 11, 2012 |archive-url = https://web.archive.org/web/20120628194807/http://northcountrytrail.org/trail/states/michigan/ |archive-date = June 28, 2012 |url-status = dead }}</ref>

==Tourism==
[[File:MackinacIslandFerry.jpg|thumb|A [[Mackinac Island]] ferry passing in front of the Mackinac Bridge.]]
During the summer months, the Upper Peninsula and Mackinac Bridge are major tourist destinations.<ref name="mtb">{{cite magazine |url = http://www.imakenews.com/tourism/e_article000226672.cfm |title = Mackinac Bridge Crossings |magazine = Michigan Tourism Business |volume = 3 |issue = 1 |date = February 24, 2004 |access-date = January 30, 2010 |url-status = dead |archive-url = https://web.archive.org/web/20110927150751/http://www.imakenews.com/tourism/e_article000226672.cfm |archive-date = September 27, 2011 }}</ref> In addition to visitors to Mackinac Island, the bridge has attracted interest from a diverse group of tourists including bridge enthusiasts, bird-watchers, and photographers.<ref name="mba-pg">{{cite web |author = Mackinac Bridge Authority |date = n.d. |url = http://www.mackinacbridge.org/photo-gallery-10/ |title = Photo Gallery |publisher = Mackinac Bridge Authority |access-date = January 30, 2010 |url-status = dead |archive-url = https://web.archive.org/web/20091222184219/http://www.mackinacbridge.org/photo-gallery-10/ |archive-date = December 22, 2009 }}</ref> The Straits area is a popular sailing destination for boats of all types, which make it easier to get a closer view to the underlying structure of the bridge.

==In media==
[[File:Mackinac Bridge from Mackinaw City.jpg|thumb|Mackinac Bridge from Michilimackinac State Park, Mackinaw City]]
On June 25, 1958, to coincide with that year's celebration of the November 1957 opening, the [[United States Postal Service]] (USPS) released a 3¢ [[commemorative stamp]] featuring the recently completed bridge.  It was entitled "Connecting the Peninsulas of Michigan" and 107,195,200&nbsp;copies were issued.<ref name="stamp">{{cite web |url = http://www.mightymac.org/mackinacbridgestamp.htm |title = Mackinac Bridge Postage Stamps |website = Mighty Mac |first = Keith |last = Stokes |access-date = March 28, 2024 }}</ref> The USPS again honored the Mackinac Bridge as the subject of its 2010 [[priority mail]] $4.90 stamp, which went on sale February 3.<ref>{{cite press release |url = https://about.usps.com/news/state-releases/mi/2010/mi_2010_0203.htm |title = U.S. Postal Service Issues Mackinac Bridge Stamp |date = February 3, 2010 |publisher = United States Postal Service |access-date = March 28, 2024 }}</ref>  The bridge authority and MDOT unveiled the stamp, which featured a "seagull's-eye view" of the landmark, with a passing [[Cargo ship|freighter]] below.<ref name="freep-stamp">{{cite news |title = New stamp commemorating Mighty Mac to be unveiled |url = https://www.theoaklandpress.com/2010/02/03/new-stamp-commemorating-mighty-mac-to-be-unveiled/ |newspaper = [[The Oakland Press]] |date = February 3, 2010 |access-date = March 28, 2024 }}</ref> Artist Dan Cosgrove worked from [[panoramic]] photographs to create the artwork. This is one of several designs that Cosgrove has produced for the USPS.<ref>{{cite press release |url = http://www.usps.com/communications/newsroom/2009/pr09_118.htm |publisher = United States Postal Service |title = 2010 Stamp Designs |date = December 30, 2009 |access-date = March 28, 2024 |archive-url = https://web.archive.org/web/20100419183649/http://www.usps.com/communications/newsroom/2009/pr09_118.htm |archive-date = April 19, 2010 }}</ref>

On April 24, 1959, Captain John S. Lappo, an officer in the [[Strategic Air Command]], operating from [[Lockbourne AFB]] flew his [[Boeing B-47 Stratojet]] beneath the bridge. Following a [[Courts-martial in the United States#General court-martial|general court-martial]], he was grounded for life.<ref>{{cite news |title = Grounded for Good |date = December 11, 1959 |url = https://heraldpalladium.newspapers.com/image/365238811/?terms=%22grounded%20for%20good%22&match=1 |newspaper = The News-Palladium |location = Benton Harbor, Michigan |page = 10 |url-access = subscription |access-date = March 28, 2024 }}</ref>

A feature-length documentary entitled ''Building the Mighty Mac'' was produced by Hollywood filmmaker Mark Howell in 1997 and was shown on [[PBS]]. The program features numerous interviews with the key people who built the structure and includes restored 16mm color footage of the bridge's construction.<ref>{{cite web |url = http://www.great-lakes.net/teach/history/macbridge/mac_4.html |title = TEACH: Building the Mackinac Bridge |website = Great Lakes Information Network |access-date = September 29, 2016 |archive-url = https://web.archive.org/web/20170206212202/http://www.great-lakes.net/teach/history/macbridge/mac_4.html |archive-date = February 6, 2017 |url-status = dead }}</ref>

The history and building of the bridge was featured in a 2003 episode of the [[History (U.S. TV channel)|History Channel]] TV show ''[[Modern Marvels]]''.<ref name="imdb">{{cite web |url = https://www.imdb.com/title/tt0905001/ |title = 'Modern Marvels' Mackinac Bridge (2003) |website = [[IMDb]] |access-date = January 30, 2010 }}</ref>

On July 19, 2007, the [[Detroit Science Center]] unveiled an {{convert|80|ft|m|adj=mid|-long}}, {{convert|19|ft|m|adj=mid|-tall}} scale model of the Mackinac Bridge. The exhibit was part of the state's 50th anniversary celebration of the bridge. [[Sherwin-Williams]] supplied authentic Mackinac Bridge-colored paint for the project.<ref name="prnw">{{cite press release |url = http://www.prnewswire.com/news-releases/detroit-science-center-to-open-mini-mac-exhibit-58160002.html |title = Detroit Science Center To Open 'Mini Mac' Exhibit |publisher = Detroit Science Center |date = June 19, 2007 |access-date = January 30, 2010 |via = PR Newswire |archive-url = https://web.archive.org/web/20121012132514/http://www.prnewswire.com/news-releases/detroit-science-center-to-open-mini-mac-exhibit-58160002.html |archive-date = October 12, 2012 |url-status = dead }}</ref>

The bridge and its maintenance crew were featured in an episode of the [[Discovery Channel]] TV show ''[[Dirty Jobs]]'' on August 7, 2007. Host [[Mike Rowe (television host)|Mike Rowe]] and crew spent several days filming the [[List of Dirty Jobs episodes|episode]] in May 2007.<ref>{{cite news |url = https://www.mackinacislandnews.com/articles/island-work-featured-on-dirty-jobs/ |title = Island Work Featured on 'Dirty Jobs' |newspaper = [[Mackinac Island Town Crier]] |first = Karen |last = Gould |date = June 2, 2007 |access-date = March 28, 2024 |url-access = subscription }}</ref><ref>{{cite web |url = https://www.imdb.com/title/tt1065824/ |title = Dirty Jobs, Season 3, Episode 5 |website = IMDb |access-date = January 30, 2010 }}</ref>

MDOT also featured the bridge on the cover of the 2007 state highway map to celebrate its 50th anniversary.<ref name="MDOT07">{{cite MDOT map |year=2007 |at=[http://img.lib.msu.edu/exhibits/map/MIRoadMaps/mdot2007.jpg Front cover] }}</ref>

{{wide image|Straits of Mackinac Panorama.jpg|1280px|2008 panorama of the bridge from [[Mackinac Island]]|100%}}

==See also==
{{Portal|Transport|Engineering|Michigan}}
* [[List of longest suspension bridge spans]]
{{clear}}

==References==
{{Reflist}}

==Further reading==
{{refbegin}}
* {{cite book |author-link = Prentiss M. Brown |last = Brown |first = Prentiss M. |year = 1956 |title = The Mackinac Bridge Story |location = Detroit |publisher = [[Wayne State University Press]] |oclc = 5392305 }}
*{{cite news |date = October 3, 1989 |title = Driver was alive in Mackinac plunge |page = 35 |work = Detroit Free Press |url = https://www.newspapers.com/clip/18625460/driver-was-alive-in-mackinac-plunge/ |access-date = March 25, 2022 |via = Newspapers.com}}
* {{cite magazine |title = Mackinac Bridge |magazine = Civil Engineering |date = May 1956 }}
* {{cite magazine |title = The Mighty Mac at 50 |magazine = Michigan History |edition = Special |volume = 9 |issue = 4 |date = July–August 2007 }}
* {{cite book |last = Ratigan |first = William |title = The Long Crossing |location = Grand Rapids, MI |publisher = Eerdmans |year = 1959 |oclc = 1686567 }}
* {{cite book |last = Ratigan |first = William |author-mask = —— |title = Straits of Mackinac! Crossroads of the Great Lakes |location = Grand Rapids, MI |publisher = Eerdmans |year = 1957 |oclc = 3478409 }}
* {{cite book |last1 = Steinman |first1 = David B. |last2 = Nevill |first2 = John T . |year = 1957 |title = Miracle Bridge at Mackinac |location = Grand Rapids, MI |publisher = Eerdmans |oclc = 1227671 }}
*{{cite news |url = http://apps.detnews.com/apps/history/index.php?id=156 |last = Zacharias |first = Pat |date = June 6, 2000 |title = The Breathtaking Mackinac Bridge |work = [[The Detroit News]] |url-status = dead |archive-url = https://archive.today/20130121103110/http://apps.detnews.com/apps/history/index.php?id=156 |archive-date = January 21, 2013 }}
{{refend}}

==External links==
{{Commons category|Mackinac Bridge}}
*[http://www.mackinacbridge.org/ Mackinac Bridge Authority]
*[http://www.michigan.gov/mdot/0,1607,7-151-9618_11016-22026--,00.html Length Comparison]
*[http://www.mightymac.org/bridge.htm Mackinac Bridge photographs and facts]
*[http://www.pobonline.com/CDA/Articles/Cover_Story/BNP_GUID_9-5-2006_A_10000000000000209422 Monitoring the Mighty Mac, Point of Beginning, 2007]
*[http://www.mackinacbridge.org/ Web cams monitoring the Mackinac Bridge]
*[https://web.archive.org/web/20140808062059/http://www.round.me/tour/1271/view The view from the top of the iconic Mackinac Bridge that connects the two peninsulas of Michigan, 2014]
*{{HAER |survey=MI-329 |id=mi0678 |title=Mackinac Straits Suspension Bridge}}
*[https://liveworldwebcams.com/mackinac-bridge-webcam-michigan/ Mackinac Bridge Live Stream]

{{MIHistory}}
{{Northern Michigan}}
{{Upper Peninsula of Michigan}}
{{Authority control}}

[[Category:Buildings and structures in Cheboygan County, Michigan]]
[[Category:Buildings and structures in Emmet County, Michigan]]
[[Category:Buildings and structures in Mackinac County, Michigan]]
[[Category:Bridges completed in 1957]]
[[Category:Bridges on the Interstate Highway System]]
[[Category:Historic Civil Engineering Landmarks]]
[[Category:Interstate 75]]
[[Category:Lake Huron Circle Tour]]
[[Category:Lake Michigan Circle Tour]]
[[Category:Road bridges in Michigan]]
[[Category:Roads with a reversible lane]]
[[Category:Suspension bridges in the United States]]
[[Category:Symbols of Michigan]]
[[Category:Toll bridges in Michigan]]
[[Category:Tolled sections of Interstate Highways]]
[[Category:Towers in Michigan]]
[[Category:Transportation in Cheboygan County, Michigan]]
[[Category:Transportation in Mackinac County, Michigan]]
[[Category:Transportation in Emmet County, Michigan]]
[[Category:Tourist attractions in Cheboygan County, Michigan]]
[[Category:Historic American Engineering Record in Michigan]]
[[Category:Tourist attractions in Emmet County, Michigan]]
[[Category:Tourist attractions in Mackinac County, Michigan]]
[[Category:1957 establishments in Michigan]]
[[Category:Steel bridges in the United States]]