RIO GRANDE CITY Population 9, 976 Altitude 238 General Port of entry with international bridge between U.S. and Mexico; seat of Starr County. Area included in Jose de Escandon's Colony of 1753; when General Zachary Taylor established Fort Ringgold in 1848, it added population and permanence. Attractions FORT RINGGOLD - One of Texas' best preserved old military posts; named for Maj. David ...