The U.S. Army Corps of Engineers operates locks across 14 dam projects crisscrossing the Tennessee and Cumberland Rivers and their reservoirs. The Tennessee River flows for 652 miles, with locks providing safe passage for barges and other commercial vessels from Knoxville, Tennessee to the Ohio River at Paducah, Kentucky. Annually, 25,000-30,000 commercial barges and 6,000-8,000 recreational vessels crisscross the Tennessee River and its reservoirs each year. The Cumberland River flows for 688 miles through southern Kentucky and north-central Tennessee to its confluence with the Ohio River near Paducah, Kentucky, and the mouth of the Tennessee River.