Interstate 75 (I-75) is a part of the Interstate Highway System that runs north–south from Miami, Florida, to Sault Ste. Marie in the Upper Peninsula of the US state of Michigan. I-75 enters the state from Ohio in the south, north of Toledo, and runs generally northward through Detroit, Pontiac and Bay City, crosses the Mackinac Bridge, and ends at the Canadian border in Sault Ste. Marie. The freeway runs for approximately 396 miles (637 km) on both of Michigan's major peninsulas. The landscapes traversed by I-75 include Southern Michigan farmland, northern forests, suburban bedroom communities, and the urban core of Detroit. The freeway also uses three of the state's monumental bridges to cross major bodies of water. There are four auxiliary Interstates in the state related to I-75, as well as nine current or former business routes, with either Business Loop I-75 or Business Spur I-75 designations.

The Mackinac Bridge is a suspension bridge that connects the Upper and 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 26,372-foot-long bridge is the world's 27th-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 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 National Scenic Trail. The bridge connects the city of St. Ignace to the north with the village of Mackinaw City to the south.