U.S. Route 31

U.S. Route 31 or U.S. Highway 31 (US 31) is a long north–south highway connecting southern Alabama to northern Michigan. Its southern terminus is at an intersection with US 90/US 98 in Spanish Fort, Alabama. Its northern terminus is at an interchange with Interstate 75 (I-75) south of Mackinaw City, Michigan.

US 31 once crossed the Straits of Mackinac by car ferry to intersect US 2 north of St. Ignace, Michigan, in the Upper Peninsula and then formerly reached Mackinaw City along the southern approaches of the Mackinac Bridge (which has been taken over by I-75). It also formerly entered downtown Mobile, Alabama, via a long bridge over Mobile Bay.

Route description

Alabama

US 31 begins in Spanish Fort, Alabama at a junction with US 90 and 98. Formerly, the route originated in Mobile, co-routed with US 90 and 98. Whereas Interstate 65 leaves the Mobile Metropolitan Area via a route on the west side of the city, US 31 leaves the Mobile area via a route on the eastern side of the metro area, passing through Bay Minette. I-65 has effectively replaced US 31 as the preferred route for through traffic, making US 31 a local connecting route.

U.S. Route 31 in Michigan

US Highway 31 (US 31) is a part of the United States Numbered Highway System that runs from Alabama to the Lower Peninsula of the US state of Michigan. In Michigan, it is a state trunkline highway that runs from the Indiana–Michigan state line at Bertrand Township north to its terminus at Interstate 75 (I-75) south of Mackinaw City. Along its 356.5-mile-long (573.7 km) route, US 31 follows the Michigan section of the St. Joseph Valley Parkway as well as other freeways and divided highways northward to Ludington. North of there, the trunkline is a rural undivided highway through the Northern Michigan tourist destinations of Traverse City and Petoskey before terminating south of Mackinaw City. Along its route, US 31 has been dedicated in memory of a few different organizations, and sections of it carry the Lake Michigan Circle Tour (LMCT) moniker. Four bridges used by the highway have been recognized for their historic character as well.

The first highways along the route of the modern US 31 corridor were the West Michigan Pike, an auto trail from 1913, and later a pair of state trunklines (the original M-11 and M-58) in 1919. These state highways were redesignated US 31 on November 11, 1926, when the US Highway System was approved. Since then, the highway has been realigned in places. The highway crossed the Straits of Mackinac by ferry for about a decade in the 1920s and 1930s before the Mackinac Bridge was built, connecting to US 2 north of St. Ignace. Later, sections were converted into freeways starting in the 1950s. These segments opened through the subsequent decades with the last one opening in 2003. Future plans by the Michigan Department of Transportation (MDOT) are to finish the St. Joseph Valley Parkway and bypass Grand Haven.

U.S. Route 31 in Indiana

U.S. Route 31 (US 31) is a part of the United States Numbered Highway System that runs from Spanish Fort, Alabama, to the Mackinaw City, Michigan. In the U.S. state of Indiana, it is a State Road that enters the state via the George Rogers Clark Memorial Bridge between Louisville, Kentucky, and Clarksville, Indiana. The 266.02 miles (428.12 km) of US 31 that lie within Indiana serve as a major conduit. Some of the highway is listed on the National Highway System. Various sections are rural two-lane highway and urbanized four-lane divided expressway. The northernmost community along the highway is South Bend near the Michigan state line.

US 31 was first designated as a US Highway in 1926. A northern (from Rochester to South Bend) and very far south section (on old US 31 W into Louisville on the K&I Bridge) of the highway originally served as part of the Dixie Highway. US 31 was the Jackson Highway from Indianapolis to Seymour. US 31 replaced the original State Road 1 (SR 1) designation of the highway which dated back to the formation of the Indiana State Road system. SR 1 ran from Clarksville through Indianapolis to South Bend and ended at the Michigan state line.