Mackinac Bridge Authority

Spanning the Straits of Mackinac since 1957

Frequently Asked Questions

Annual Bridge Walk

For safety reasons, we do not allow banners, flags, umbrellas, or signs. We ask that you exercise good judgement for the safety of all who participate in this family orientated event.

Bridge Services


Effective Friday, March 13, the Mackinac Bridge indefinitely suspended its motorcycle trailering program as part of measures to help slow the spread of the Covid-19 virus.



Effective Friday, March 13, the Mackinac Bridge indefinitely suspended its driver assistance program as part of measures to help slow the spread of the Covid-19 virus.



Effective Friday, March 13, the Mackinac Bridge indefinitely suspended its bicycle trailering program as part of measures to help slow the spread of the Covid-19 virus.

Bicyclists are not allowed to cross the Mackinac Bridge on their own.


The width of the roadway is 54 feet. The outside lanes are 12 feet wide (2), the inside lanes are 11 feet wide (2), the center mall is 2 feet wide, and the catwalk, curb and rail width is 3 feet on each side – totaling 54 feet. The stiffening truss width in the suspended span is 68 feet wide making it wider than the roadway it supports.

All suspension bridges are designed to move to accommodate wind, change in temperature, and weight. It is possible that the deck at center span could move as much as 35 feet (east or west) due to high winds. This would only happen under severe wind conditions. The deck would not swing or “sway” but rather move slowly in one direction based on the force and direction of the wind. After the wind subsides, the weight of the vehicles crossing would slowly move it back into center position.

The steel superstructure will support one ton per lineal foot per roadway (northbound or southbound). The length of the steel superstructure is 19,243 feet. Each direction will, therefore, support 19,243 tons. The answer is 38,486 tons (2 x 19,243 tons).


Although the Mackinac Bridge remained one of the four longest suspension bridges for more than 40 years, several bridges built since 1998 have surpassed it. Suspension bridges are commonly measured by main span length which is the distance between towers. By this ranking, the Mackinac Bridge is currently the twenty fourth longest suspension bridge in the world, and the third longest suspension bridge in North America. However, due to the Mackinac Bridge’s long side spans it remains among the top five longest suspension bridges in the world in suspended length; and the longest in the western hemisphere measuring 7,400 ft from bent pier to bent pier. The suspended length is the length by which the bridge deck is only supported by the cables. By total length the Mackinac Bridge, at 5 miles long, remains one of the longest bridges of its kind. By comparison, the Akashi Kaikyō Bridge in Japan, which is currently considered the longest suspension bridge in the world with a main span length of 6,532 ft, is less than 2.5 miles long in total length.

Figure 1. Suspension bridges are often ranked according to the main span length, which is the length between towers. However, the total suspended length of a suspension bridge can include its side spans.


Table 1. Common ranking of suspension bridges of the world by main span length

Table 2. Ranking of suspension bridges in the Western Hemisphere by suspended lengths.



The height of the roadway at mid-span is approximately 200 feet above water level. The vertical clearance at normal temperature is 155 feet at the center of the main suspension span and 135 feet at the boundaries of the 3,000 ft. navigation channel.

The Mackinac Bridge is located in northern Michigan at the Straits of Mackinac. The bridge connects Michigan’s upper and lower peninsulas. Mackinaw City is located at the south end of the bridge. St. Ignace is located at the north end of the Mackinac Bridge.

There are two large finger joints at the towers to accommodate all the expansion of the suspended spans. There are 11 smaller finger joints and 5 sliding joints across the Mackinac Bridge. In addition, there are 13 expansion joints for the south viaduct spans – one for each of these simple spans. This adds up to a total of 31 total joints.


Michigan has two peninsulas – the Upper and the Lower. The closest point between the peninsulas is the Straits of Mackinac – approximately 4 miles in length. Because of the distance and difficulty to get back and forth, people were interested in improving transportation and commerce. In 1923, the State Highway Department started ferry service in the Straits area in response to demand for service. Ferry boats were very popular and the demand increased. In the last year of operation, the ferries transported 900,000 vehicles. The ferries couldn’t keep up with the demand. It proved that if you provided a connection, people would use it.

The bridge was opened to traffic on November 1, 1957.

Bonds ($99,800,000) for the project were issued in early 1954. The proceeds to the Authority amounted to $96,400,033.33. The cost to design the project was $3,500,000 (Steinman Company). The cost to construct the bridge was $70, 268,500. Two primary contractors were hired to build the bridge: American Bridge for superstructure – $44,532,900; and Merritt-Chapman and Scott of New York for the foundations – $25,735,600. The remainder of the proceeds from the bond sale was used to service the bond debt both during and after construction. Tolls could not be collected until the bridge was opened to traffic on November 1, 1957.

Five men died during the construction of the Mackinac Bridge. The names of the five workers and dates of death: Frank Pepper, September 16, 1954; James R. LeSarge, October 10, 1954; Albert Abbott, October 25, 1954; Jack C. Baker, June 6, 1956; and, Robert Koppen, June 6, 1956. Information about the five workers who died during construction of the Mackinac Bridge can be found in Mr. Larry Rubin’s book titled “Bridging the Straits”.

There are no bodies buried in the concrete supports of the Mackinac Bridge. Five workers died during the construction of the Mackinac Bridge. One died in a diving accident; one fell in a caisson while welding; one fell a couple of feet into the water and drowned; and two fell from a temporary catwalk near the top of north tower. All but one body was recovered. When the two workers fell from the temporary catwalk, they fell approximately 550 feet. One body was recovered immediately. A three-day search for the other worker ended without success.

All of the general information that we formerly sent out by mail has been placed on our web site for your convenience. Please browse through our various menu items such as facts and figures, the photo gallery and the history pages. You are welcome to download pictures from our web site to use in your report.

Mackinac is Canadian French, short for Michilimackinac, from early Ojibwa “Missilimaahkinaank” which means “at the territory of the Mishinimaki”. The Mishinimaki was an extinct division of the Ojibwa formerly living in this region.

The French pronounced it “aw” but spelled it “ac”. The British heard it pronounced “aw” so they spelled it that way. Whichever way you see it spelled, it is always pronounced “aw”.


For information about Michigan, please go to our Links of Interest button and click on “Travel Michigan”.

For travel information, We recommend that you contact agencies such as Travel Michigan, the Mackinaw Chamber of Commerce, the Mackinaw Tourist Bureau, the St. Ignace Chamber of Commerce, and the St. Ignace Tourist Bureau.

To access these web sites, go to
Links of Interest on our web site menu; then select the tourism agency of your choice. For information about Mackinac Island, please contact the Mackinac Island Tourism Bureau at 906-847-3783 or visit their web site at

To get a side profile schematic, try contacting Errolgraphics Inc., P.O. Box 40800, Portland, Oregon 97240. They produced a side schematic in 1997. Their web site is

The live camera picture of the Mackinac Bridge is a very popular feature of our site and others.  The camera images are configured to automatically update every 60 seconds. The time stamp indicates the last captured image. If your browser does not display the most recent image, you may need to refresh the browser.

The live camera picture of the Mackinac Bridge is a very popular feature of our site and others. The Mackinac Bridge currently has 4 cameras. The cameras show the views from the Mackinac Bridge administration building looking south, the Mackinac Bridge dock in St. Ignace looking south, the Bridge View Park in St. Ignace looking south, and one in Mackinaw City looking north.

The Bridge at Mackinac

In the land of Hiawatha,
Where the white man gazed with awe
At a paradise divided
By the straits of Mackinac

Men are dredging, drilling, blasting,
Battling tides around the clock,
Through the depths of icy water,
Driving caissons down to rock.

Fleets of freighters bring their cargoes
From the forges and the kilns;
Stones and steel – ten thousand barge-loads –
From the quarries, mines, and mills.

Now the towers, mounting skyward,
Reach the heights of airy space.
Hear the rivet-hammers ringing,
Joining steel in strength and grace.

High above the swirling currents,
Parabolic strands are strung;
From the cables, packed with power,
Wonder-spans of steel are hung.

Generations dreamed the crossing;
Doubters shook their heads in scorn.
Brave men vowed that they would build it –
From their faith a bridge was born.

There it spans the miles of water,
Speeding millions on their way –
Bridge of vision, hope and courage,
Portal to a brighter day.

Bay Windpower and Crystal Flash, both Grand Rapids companies, have constructed two of five wind turbines in Mackinaw City. The two 256 foot wind turbine generators will produce an estimated 4 million kilowatt hours of power annually.

Through an agreement with Consumers Energy, Bay Windpower will provide the first 4 million kilowatt hours of power to customers enrolled in the Consumers Energy Green Power Pilot Program. Energy customers in 68 counties who are interested in purchasing wind power produced at the Mackinaw City site can do so by enrolling in the Consumers Energy Green Power Pilot Program. Details are available through the Consumers Energy web site –