State Route 157 begins at a 4-way stop with US 278. South of the 4-way stop, the road continues as Cullman County Road 719. Throughout North Cullman, AL-157 is oriented in an east-to-west trajectory, passing by a large Buick/GMC dealership at its junction with U.S. 31, then past several restaurants, and ultimately reaching I-65. In northern Cullman County, the route makes a gradual curve north. The county line with Morgan County is marked in the middle of a steep downgrade/upgrade known as Battleground Mountain for the nearby town of Battleground. After this descent/ascent, the route makes a short journey through hilly terrain until it reaches Danville, where it junctions with CR-55 and CR-41. After these junctions, the route becomes flat. It crosses the line into Lawrence County and shortly junctions with SR-36, which leads to Hartselle and Wren. Eventually, the route reaches Moulton, where it serves as the main north-to-south thoroughfare for the east district of Moulton, which contains most of its restaurants and shops. It eventually junctions with Alabama State Route 24/Corridor V and Alabama State Route 33. Past this point, the route passes through once again hilly terrain as it passes through Hatton and Alabama State Route 101. It eventually reaches the Colbert County line and then junctions with Alabama State Route 20. The concurrent routes reach Muscle Shoals, where the route turns north in a concurrency with Alabama State Route 133, losing Alabama State Route 20. Past this point, the route crosses the Tennessee River and the Lauderdale County line. The route passes through Florence on a freeway directly through town, junctioning with U.S. 72 and U.S. 43, also losing Alabama State Route 133 and gaining Alabama State Route 17 before and at this specific interchange respectively. On the north side of town, the route re-engages in a concurrency with S.R. 133 and now S.R. 17. After a short concurrency, the route drops S.R. 17 and continues west with S.R. 133. Eventually, it turns off of the concurrency and heads north, crossing the Tennessee state line directly beside the Natchez Trace Parkway. The route becomes Tennessee State Route 227, which loops around and acts as the northern terminus to Alabama State Route 101. This route is an important connector between multiple cities in Northwestern Alabama with S.R. 20, S.R. 24, and S.R. 13.
History
SR 157 has been four-laned along almost its entire length. This project, which began in the 1980s, was finally completed in the summer of 2007.
