US Route 31

U.S. Route 31 is a long north-south highway connecting northern Michigan to southern Alabama, with termini at Interstate 75 near Mackinaw City, Michigan, and U.S. Route 90 and U.S. Route 98 at Spanish Fort, Alabama. It formerly reached Mackinaw City along the southern approaches of the Mackinac Bridge (Interstate 75) in the north and downtown Mobile, Alabama, in the south.