Rancho Viejo is a town in Cameron County, Texas, United States. The population was 1,754 at the 2000 census. The town is named from a ranch in that area named 'Rancho Viejo' or old ranch. This ranch was owned by Blas Maria de la Garza Falcón, whose name was given to a near by dam, Falcon Dam. Rancho Viejo apartments for rent comparison page shows most up to date rent information on Rancho Viejo apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.