W. D. Mayo Lock and Dam, Lock and dam in LeFlore County, United States.

The W. D. Mayo Lock and Dam is a lock and dam facility on the Arkansas River in LeFlore County. The structure stretches across the river with twelve gates designed to help vessels navigate changes in water level as they pass through the waterway.

Construction began in May 1966, closure was completed on October 15, 1970, and the lock and dam became operational for navigation in December 1970. It is the first lock and dam west of the Arkansas-Oklahoma state line and the fourteenth facility in sequence from the start of the McClellan-Kerr Arkansas River Navigation System. The U.S. Army Corps of Engineers manages it.

The facility bears the name of a Sallisaw business leader who advocated for the development of river infrastructure in Oklahoma.

Visitors can observe the facility during the day and watch vessels passing through as the gates operate. It is best to find a viewing spot with clear sight lines to see how the system works.

The lock chamber measures 110 by 600 feet and uses single-lift miter gates, with a normal lift of 20 feet and a maximum of 22 feet. It is the first lock and dam west of the Arkansas-Oklahoma state line, at navigation mile 319.6.