Lake Livingston is a reservoir located in the East Texas Piney Woods. Lake Livingston was built, and is owned and operated, by the Trinity River Authority of Texas (TRA) under contract with the City of Houston for water-supply purposes. The lake is the second-largest lake located wholly within the state of Texas (only the Sam Rayburn Reservoir is larger). The Livingston Dam, constructed across the Trinity River approximately 7 miles (11 km) southwest of the city of Livingston is 2.5 miles (4 km) in length and has an average depth of 55 feet (17 m).