The Cumberland River is a major waterway of the Southern United States. The 688-mile-long river drains almost 18,000 square miles of southern Kentucky and north-central Tennessee. The river flows generally west from a source in the Appalachian Mountains to its confluence with the Ohio River near Paducah, Kentucky, and the mouth of the Tennessee Riv…The Cumberland River is a major waterway of the Southern United States. The 688-mile-long river drains almost 18,000 square miles of southern Kentucky and north-central Tennessee. The river flows generally west from a source in the Appalachian Mountains to its confluence with the Ohio River near Paducah, Kentucky, and the mouth of the Tennessee River. Major tributaries include the Obey, Caney Fork, Stones, and Red Rivers.