One of Texas' best preserved old military posts; named for Maj. David Ringgold, first army officer killed in Battle of Palo Alto that opened Mexican War. Established after Mexican War for protection against Indians and to assure Rio Grande as national boundary; deactivated in 1944. Among distinguished landmarks are Lee House, once occupied by Col. Robert E. Lee when he commanded Department of Texas before the Civil War, and old post hospital. Portions of fort are now part of Rio Grande City school system. Off U.S. 83 at east limit.