U.S. Route 31 - History

History

In the 1930s, US 31 continued at Saint Ignace across the Straits of Mackinac, and junctioned with U.S. Route 2 (Mackinac Trail and what later became M-123).

Before the Interstate era, US 31 was a major north–south highway. Interstate 65 supplants US 31 and either 31W or 31E as a through route between Indianapolis and Mobile. South of Indianapolis, all segments of US 31 not coinciding with Interstate 65 have been reduced to roads largely of local use. Interstate 196 now carries the route of US 31 between Holland, Michigan, and St. Joseph, Michigan. All of US 31 between Ludington, Michigan, and Indianapolis, Indiana, is divided highway—some of it is freeway, including a bypass route of South Bend, Indiana. The segment between South Bend and Indianapolis is scheduled for upgrade or replacement with Interstate-standard freeway (see U.S. Route 31 in Indiana). Environmental impact studies have shown that the fifth phase of the then-to-be-constructed freeway segment between Napier Avenue near Benton Harbor, Michigan, and I-94 may not be complete until 2015 (see St. Joseph Valley Parkway).

The portion of I-75 north of US 31's northern terminus toward the Mackinac Bridge was designated US 31 prior to the 1990s and was US 31's most northern portion to be built to freeway status. Since its truncation at the I-75 junction, however, the most northern segment of US 31 freeway ends near Ludington.

At its southern end, US 31 originally went further west than it currently does, passing through Spanish Fort, Alabama. It crossed Mobile Bay via several narrow bridges, including the Admiral Raphael Semmes Bridge, a drawbridge spanning the Tensaw River. It turned north along the east bank of the Mobile River, crossing the river into Plateau, Alabama, over the Cochrane Bridge (removed), another old drawbridge where the current Cochrane–Africatown USA Bridge is now located. It then turned south to end at U.S. Route 90. It now officially ends at U.S. Route 98 in Spanish Fort, Alabama.