Alternate U.S. Route 72 (US 72 Alt.) exists in Alabama on the south side of the Tennessee River between Muscle Shoals and Decatur, while US 72 follows on the north side of the river between Florence and Athens. US 72A crosses the Tennessee River at Decatur, along with U.S. Highway 31, and follows the entire route of Interstate 565. SR-20 was co-signed with US 72A from Muscle Shoals to Huntsville but has since been truncated to the junction of I-65 just east of Decatur.