The Mackinac Bridge carries Interstate 75 across the Straits of Mackinac between St. Ignace and Mackinaw City, linking Michigan’s Upper and Lower Peninsulas by road since its opening on November 1, 1957. Nearly five miles long, with a 3,800-foot main span, it ranks among the longest suspension bridges in the world and remains the longest suspension bridge between anchorages in the Western Hemisphere. Built under engineer David B. Steinman after decades of proposals, ferry crowding, and delays, it overcame severe wind, deep water, and winter ice. The bridge ended ferry service, became a Michigan symbol, and remains a major transportation link and engineering landmark.