John C. Stennis Lock and Dam, Lock and dam system on Tennessee-Tombigbee Waterway in Lowndes County, United States.

John C. Stennis Lock and Dam is a water control structure on the Tennessee-Tombigbee Waterway that manages water levels and allows large cargo vessels to pass through. The facility creates Columbus Lake, which stretches for many miles upstream and serves as a crucial point for navigation.

The John C. Stennis Lock and Dam was originally named Columbus Lock and Dam, after the nearby city. It is one of four lock and dam structures on the Tennessee-Tombigbee Waterway, which generally lie along the original course of the Tombigbee River. It was later renamed for John C. Stennis, the longtime U.S. Senator from Mississippi.

The structure carries the name of John C. Stennis, the Mississippi senator it honours, and it is one of four lock and dam structures on the Tennessee-Tombigbee Waterway that follow the original course of the Tombigbee River. Visitors watching vessels pass through the chamber see that river navigation in this stretch now runs through a managed channel rather than the free-flowing Tombigbee.

The complex has several areas where visitors can view the structure and surrounding waterways. Fishing and boating are available year-round on the created lake, with different opportunities depending on the season.

It is one of four lock and dam structures on the Tennessee-Tombigbee Waterway, and it generally lies along the original course of the Tombigbee River. The pool it impounds is called Columbus Lake, after the nearby city of Columbus, Mississippi.