The Cahaba River is the longest substantially free-flowing river in Alabama and is among the most scenic and biologically diverse rivers in the United States. It is a major tributary of the Alabama River and part of the larger Mobile River basin. It is the primary drinking water source for one-fifth of the state’s people in the Birmingham metro area. Flowing from its headwaters northeast of Birmingham until it reaches the Alabama River southwest of Selma, the Cahaba River is 194 miles long and drains an area of 1,870 square miles.
The name Cahaba is derived from the Choctaw words oka meaning “water” and aba meaning “above.”