The Great Sauk Trail, connecting Detroit, Chicago, and Green Bay, Wisconsin, crossed the St. Joseph River at a shallow spot near Mottville. As pioneers moved westward, the federal government surveyed the trail and converted it into the Chicago Road, now U.S. 12, in 1825. The first Chicago Road bridge across the river near Mottville was a substantial timber structure built in 1833-34 by contractor Hart L. Stewart, and a pile-supported bridge replaced it in 1845. In 1867, Mahlon Thompson and Joseph Miller built a covered Burr arch truss, and the ruins of its stone-block abutments remain visible upstream. The present three-span camelback bridge was built in 1922 and is the longest Michigan example of a reinforced concrete camelback bridge. Built by contractors Smith and Nichols of Hastings under the direction of State Bridge Engineer C.A. Melick, it reflects the Michigan State Highway Department's pioneering use of standardized concrete bridge designs; by the early 1920s, the department had established standard plans for camelback spans of 50, 60, 70, 75, and 90 feet, and this bridge contains three identical 90-foot spans. Found primarily in Michigan and Ontario, Canada, camelback bridges are well represented by this design. In 1990, U.S. 12 was rerouted over a new bridge, and the 1922 camelback bridge was preserved as an engineering landmark for foot traffic by the Michigan Department of Transportation.