The Mackinac Bridge, also called the Mighty Mac or Big Mac, is a suspension bridge that connects the Upper and Lower Peninsulas of Michigan. It crosses the Straits of Mackinac, a waterway that links Lake Michigan and Lake Huron, two of the Great Lakes. Opened in 1957, the bridge is 26,372 feet long (4.995 miles or 8.038 kilometers). It holds the title of the world's 29th-longest main span and is the longest suspension bridge between anchorages in the Western Hemisphere. The Mackinac Bridge is part of Interstate 75 (I-75) and carries the Lake Michigan and Huron sections of the Great Lakes Circle Tour across the straits. It is also a part of the U.S. North Country National Scenic Trail. The bridge connects the city of St. Ignace in the north to the village of Mackinaw City in the south.
Plans for the bridge began in the 1880s. It was designed by engineer David B. Steinman and completed in 1957 after many years of effort to start construction. The Mackinac Bridge has since become a famous symbol of Michigan.
Length
The bridge opened on November 1, 1957, connecting two peninsulas that had been linked by ferries for many years. At the time, the bridge was officially named the "world's longest suspension bridge between anchorages," which allowed a special 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. Much longer distances from one anchorage to another have been built in the Eastern Hemisphere, including the Akashi Kaikyō Bridge in Japan (6,532 ft or 1,991 m). However, the long sections leading to the anchorages on the Mackinac Bridge make its total shoreline-to-shoreline length of 26,372 feet (8,038 m)—28 feet (8.5 m) short of five miles (8.0 km)—longer than the Akashi Kaikyō Bridge (2.4 mi or 3.9 km).
The length of the bridge's main span is 3,800 feet (1,158 m), which makes it the third-longest suspension span in the United States and the 29th longest suspension span worldwide. It is also one of the world's longest bridges overall.
History
The Algonquian people who lived in the straits area before Europeans arrived in the 17th century called the region Michilimackinac, which means "Place of the Great Turtle" in their language. This name is thought to describe the shape of Mackinac Island. Some experts disagree about the meaning of the word. Trading posts at the Straits of Mackinac had the most people during the summer trading season. These places also became meeting spots for different Native American tribes.
As use of the state’s mineral and timber resources grew in the 19th century, the area became an important transportation center. In 1881, three railroads that reached the Straits—Michigan Central, Grand Rapids & Indiana, and Detroit, Mackinac & Marquette—created the Mackinac Transportation Company. The company operated a railroad car ferry service across the straits to connect the two peninsulas.
Improved highways along the eastern shores of the Lower Peninsula brought more car traffic to the Straits region starting in the 1910s. In 1923, the state of Michigan started an automobile ferry service between Mackinaw City and St. Ignace. This service used nine ferry boats and carried up to 9,000 vehicles daily. Traffic backups could stretch as far as 16 miles (26 km).
After the Brooklyn Bridge opened in 1883, some people imagined a similar structure across the Straits of Mackinac. In 1884, a store owner in St. Ignace published an advertisement with a drawing of the Brooklyn Bridge and the caption, "Proposed bridge across the Straits of Mackinac."
The idea of a bridge was discussed in the Michigan Legislature as early as the 1880s. At that time, the Straits of Mackinac area was becoming a popular tourist destination, especially after Mackinac National Park was created on Mackinac Island in 1875.
At a July 1888 meeting of the Grand Hotel’s board of directors on Mackinac Island, Cornelius Vanderbilt II suggested building a bridge across the straits, similar to one being built in Scotland. He believed the bridge would help trade and extend the hotel’s tourist season.
No action was taken for many years. In 1920, the Michigan state highway commissioner proposed a floating tunnel across the straits. In 1923, the state legislature ordered the State Highway Department to start ferry service across the strait. As ferry use grew, more people supported building a bridge. Chase Osborn, a former governor, wrote:
By 1928, ferry service had become very popular and expensive to operate. Governor Fred W. Green ordered a study on building a bridge. The study found the idea was possible, with an estimated cost of $30 million (equivalent to $432 million in 2024).
In 1934, the Michigan Legislature created the Mackinac Straits Bridge Authority to explore ways to build and fund the bridge. The Authority tried to get federal money during the Great Depression but failed. The U.S. Army Corps of Engineers and President Franklin D. Roosevelt supported the project, but Congress did not provide funds. Between 1936 and 1940, the Authority selected a bridge route and conducted geological studies.
Early bridge plans included a three-lane roadway, a railroad crossing, and a design similar to the San Francisco–Oakland Bay Bridge. However, building an anchorage in the deepest part of the straits might have been difficult. A 4,000-foot (1,219 m) concrete causeway was built in shallow water from 1939 to 1941. Engineers faced challenges from ice forces during winter freezes.
Work on the bridge was paused because of World War II. The Mackinac Straits Bridge Authority was abolished in 1947, but a new Mackinac Bridge Authority was created in 1950. Engineers were hired in 1950, and by 1951, the state legislature approved $85 million (equivalent to $804 million in 2024) in bonds for construction. A weak bond market delayed the project for over a year.
David B. Steinman became the design engineer in 1953. By the end of that year, contracts were signed. The total cost was estimated at $95 million (equivalent to $887 million in 2024), with completion expected by November 1, 1956. Tolls would pay for the bridge over 20 years. Construction began on May 7, 1954, under two major contracts. The Merritt-Chapman and Scott Corporation handled substructure work for $25.7 million (equivalent to $240 million in 2024), while the American Bridge Division of United States Steel built the steel superstructure for $44 million (equivalent to $407 million in 2024).
Construction took three and a half years, using the 1939–1941 causeway. The project cost $100 million and resulted in the deaths of five workers. None of them are buried in the bridge. It opened on November 1, 1957, and ferry service ended the same day. The bridge was formally dedicated on June 25, 1958.
G. Mennen Williams was governor during construction. He paid the first toll (then $3.25, equivalent to $37.26 in 2025) and later started the tradition of governors walking across the bridge on Labor Day. Senator Prentiss M. Brown, called the "father of the Mackinac Bridge," was honored with a special memorial token.
The bridge reached its 100 millionth crossing on June 25, 1998, exactly 40 years after its dedication. Its 50th anniversary was celebrated on November 1, 2007. In 2010, the American Society of Civil Engineers designated the bridge a National Historic Civil Engineering Landmark.
Facts and figures
The Mackinac Bridge is a toll bridge on Interstate 75 (I-75). The US Highway 27 (US 27) designation was first used on the bridge. In November 1960, parts of I-75 opened from Indian River north to the southern end of the bridge in Mackinaw City, and US 27 was no longer used on the bridge. It is one of only three sections of I-75 that charge tolls. The other two are the American half of the International Bridge near Sault Ste. Marie, Michigan, and Alligator Alley in Florida. The current toll is $4.00 for cars and $5.00 per axle for trucks. In 2007, the Mackinac Bridge Authority increased the toll to fund a $300 million renovation project, which would replace the bridge deck completely.
Painting the bridge takes seven years. After the painting is finished, the process begins again. The current painting project started in 1999 and was expected to take 20 years because lead-based paint must be removed, which requires special disposal methods.
The bridge celebrated its 150 millionth vehicle crossing on September 6, 2009.
Key details about the bridge:
– Length from one cable bent pier to the other: 7,400 feet (2,256 meters).
– Total roadway width: 54 feet (16.5 meters). Two outside lanes: 12 feet (3.7 meters) each. Two inside lanes: 11 feet (3.4 meters) each. Center mall: 2 feet (0.61 meters). Catwalk, curb, and rail: 3 feet (0.91 meters) on each side.
– Width of the stiffening truss in the suspended span: 68 feet (20.7 meters).
– Depth of the stiffening truss: 38.1 feet (11.6 meters).
– Height of the roadway at mid-span: about 200 feet (61 meters) above water.
– Vertical clearance at normal temperature: 155 feet (47 meters) at the center of the main suspension span. 135 feet (41 meters) at the edges of the 3,000-foot-wide (914 meters) navigation channel.
– Construction cost: $99.8 million (equivalent to $850 million in 2024).
– Height of towers above water: 552 feet (168 meters).
– Maximum depth of towers below water: 210 feet (64 meters).
– Depth of water beneath the center of the bridge: 250 feet (76 meters).
– Main cables: Each cable has 12,580 wires. Each wire is 0.196 inches (0.498 centimeters) in diameter. Each cable is 24.5 inches (62.23 centimeters) in diameter. Total length of wire in the main cables: 42,000 miles (68,000 kilometers).
– Total vehicle crossings in 2005: 4,236,491 (about 11,608 per day).
– Speed limit: 45 miles per hour (72 kilometers per hour) for passenger cars, 20 miles per hour (32 kilometers per hour) for heavy trucks. Heavy trucks must stay 500 feet (150 meters) apart from the vehicle ahead.
Five workers died during the bridge’s construction:
– Diver Frank Pepper died on September 16, 1954, after ascending too quickly from 140 feet (43 meters) underwater. He suffered the bends despite being taken to a decompression chamber.
– James LeSarge, 26, fell 40 feet (12 meters) into a caisson on October 10, 1954, and likely died from head injuries.
– Albert Abbott, 40, fell four feet (1.2 meters) into water on October 25, 1954, while working on a narrow beam. Witnesses believe he had a heart attack.
– Jack Baker and Robert Koppen, both 28, died when a catwalk collapsed near the north tower on June 6, 1956. Koppen’s body was never found. Another worker suffered a broken ankle.
All five workers are remembered on a plaque near the bridge’s northern end (Bridge View Park). No bodies are embedded in the concrete, as some stories suggest.
One worker died after the bridge was completed. Daniel Doyle fell 60 to 70 feet (18 to 21 meters) from scaffolding on August 7, 1997. He survived the fall but died from exposure to cold water (50 °F or 10 °C). His body was found the next day in 95 feet (29 meters) 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 a 36-inch-high (91 centimeter) railing. The driver lost control due to excessive speed, not high winds.
– On March 2, 1997, Richard Alan Daraban drove his car, a 1996 Ford Bronco, over the edge. This was later determined to be a suicide.
On September 10, 1978, a small private plane carrying three United States Marine Corps Reserve officers crashed into a suspension cable during heavy fog. All three men died.
Except for the annual Mackinac Bridge Walk on Labor Day, the bridge is not open to pedestrians. Suicides by jumping from the bridge have been rare. The most recent confirmed case occurred on November 4, 2025. No jumps have happened during the annual bridge walks. As of 2013, about a dozen suicides by jumping were confirmed. The Mackinac Bridge Authority does not share specific numbers about this.
Some people have difficulty crossing bridges, a condition called gephyrophobia. The Mackinac Bridge Authority offers a Drivers Assistance Program for
Bridge Walk
The first Mackinac Bridge Walk took place in 1958 and was led by Governor G. Mennen Williams. This event occurred during the Bridge's Dedication Ceremony in late June. Since 1959, the walk has been held on Labor Day. Until 2018, school buses from nearby districts transported participants from Mackinaw City to St. Ignace to start the walk. Thousands of people, usually led by the governor of Michigan, walk the five-mile (8 km) long bridge from St. Ignace to Mackinaw City. Before 1964, the walk began in Mackinaw City and ended in St. Ignace. Until 2017, two lanes of the bridge remained open for vehicles during the event. In 2017, the policy changed to close the entire bridge to vehicle traffic during the walk. The Bridge Walk is the only day each year when hikers can walk this part of the North Country National Scenic Trail.
Tourism
During the summer, the Upper Peninsula and the Mackinac Bridge are important places for tourists. In addition to visitors to Mackinac Island, the bridge has attracted many different types of visitors, including people who enjoy bridges, bird-watchers, and photographers. The Straits area is a popular spot for sailing boats of all kinds, which makes it easier to see the structure beneath the bridge.
In media
On June 25, 1958, the United States Postal Service (USPS) released a 3¢ commemorative stamp to mark the opening of the Mackinac Bridge in November 1957. The stamp was named "Connecting the Peninsulas of Michigan," and 107,195,200 copies were printed. In 2010, the USPS honored the bridge again with a $4.90 priority mail stamp. It was sold on February 3, 2010. The Mackinac Bridge Authority and the Michigan Department of Transportation (MDOT) introduced the stamp, which showed a view of the bridge from the perspective of a seagull, with a ship passing below. Artist Dan Cosgrove used panoramic photographs to create the design. This is one of several stamps Cosgrove has made for the USPS.
On April 24, 1959, Captain John S. Lappo, a Strategic Air Command officer based at Lockbourne AFB, flew his Boeing B-47 Stratojet beneath the Mackinac Bridge. After a military court-martial, he was banned from flying for life.
In 1997, filmmaker Mark Howell produced a documentary titled Building the Mighty Mac for PBS. The film includes interviews with people who helped build the bridge and restored color footage of its construction.
The bridge's history and construction were highlighted in a 2003 episode of the History Channel's Modern Marvels series.
On July 19, 2007, the Detroit Science Center displayed an 80-foot-long (24 m), 19-foot-tall (5.8 m) scale model of the Mackinac Bridge. The exhibit was part of a celebration marking the bridge's 50th anniversary. Sherwin-Williams provided paint that matched the bridge's original colors for the model.
In 2007, the Mackinac Bridge and its maintenance team were featured in an episode of the Discovery Channel's Dirty Jobs. Host Mike Rowe and his crew filmed the episode in May 2007.
To celebrate the bridge's 50th anniversary, the Mackinac Bridge appeared on the cover of the 2007 Michigan state highway map, produced by the Michigan Department of Transportation (MDOT).