The McClellan–Kerr Arkansas River Navigation System (MKARNS) is part of the United States inland waterway system originating at the Tulsa Port of Catoosa and running southeast through Oklahoma and Arkansas to the Mississippi River. The total length of the system is . It was named for two Senators, Robert S. Kerr (D-OK) and John L. McClellan (D-AR), who pushed its authorizing legislation through Congress. The system officially opened on June 5, 1971. President Richard M. Nixon attended the opening ceremony. It is operated by the Army Corps of Engineers.