PRESIDIO, TEXAS. Presidio is on the Rio Grande, Farm Road 170, and State Highway 67 eighteen miles south of Shafter in southern Presidio County. The surrounding area is the oldest continuously cultivated area in the United States. Farmers have lived at Presidio since 1500 B.C. By 1400 A.D. the area Indians lived in small, close-together settlements, which the Spaniards later called pueblos (see PUEBLO).
Full article on the Texas State Historical Association's Handbook of Texas Online