U.S. Route 331
|Auxiliary route of US 31|
|Length:||151 mi (243 km)|
|South end:||US 98 / SR 30 / SR 83 at Santa Rosa Beach, FL|
|US 29 in Brantley, AL|
|North end:||US 80 / US 82 / SR 6 / SR 8 / SR 9 / SR 21 at Montgomery, AL|
U.S. Route 331 is a spur of U.S. Route 31. It currently runs for 151 miles (243 km) from Montgomery, Alabama at U.S. Route 80 and U.S. Route 82 to Santa Rosa Beach, Florida east of Fort Walton Beach at U.S. Route 98. Unlike U.S. Route 131, U.S. Route 231, and U.S. Route 431, U.S. 331 never intersects with its "parent" route, U.S. Route 31; the two routes come within 4 miles (6.4 km) of each other in Montgomery.
U.S. 331 begins at an intersection with U.S. Route 98 in Santa Rosa Beach in Walton County. It then crosses the Choctawhatchee Bay on the Clyde B. Wells Bridge, a 2.27 miles (3.65 km) long span, and enters the eastern side of Freeport. As it continues north, a spur route of U.S. 331 branches off and goes southwest back into town. The main route continues north for several miles before intersecting Interstate 10 and forming a concurrency with US 90 in DeFuniak Springs. The concurrency runs westward briefly until U.S. 331 branches off and continues to the northwest. It moves through a few small communities before passing through the town of Paxton and crossing into Covington County, Alabama.
Once crossing the state line, U.S. 331 immediately enters Florala, where it starts a concurrency with Alabama State Route 54 on the east side of town. The highway continues into downtown Florala, where Alabama State Route 55 joins the concurrency (this intersection serves as a terminus for AL-54).
U.S. 331 continues northward to Opp, where it becomes concurrent with U.S. 84 as a bypass around the eastern side of town. A business route of U.S. 331 continues northward through town and rejoins U.S. 331 north of Opp, just after U.S. 84 leaves the concurrency with U.S. 331. The highway then continues northward and enters Crenshaw County. It keeps north and into the town of Brantley, where U.S. 29 forms a concurrency with U.S. 331.
The highways continue north into Luverne, where U.S. 29 turns northeast and U.S. 331 turns northwest as they leave town. U.S. 331 soon turns back to the north and passes through several small communities before entering Montgomery County. It passes through several more small communities before entering the southern part of the city of Montgomery. It then intersects the southern bypass of the city (U.S. 80 and U.S. 82). This intersection serves as the northern terminus for U.S. 331.
- U.S. Route 98 at Santa Rosa Beach, Florida
- State Road 20 at Freeport
- Interstate 10 at DeFuniak Springs, Florida
- U.S. Route 90 at DeFuniak Springs, Florida
- Alabama State Route 54 and Alabama State Route 55 in Florala
- U.S. Route 84 at Opp, Alabama
- U.S. Route 29 from Brantley to Luverne, Alabama
- Alabama State Route 10 in Luverne
- Alabama State Route 97 in Highland Home
- U.S. Route 80 and U.S. Route 82 in Montgomery, Alabama
- US Highways from US 1 to US 830 Robert V. Droz