Rancho Viejo is a town in Cameron County, Texas, United States. The town is named from a ranch in that area named “Rancho Viejo” (Old Ranch). This ranch was owned by Blas María de la Garza Falcón, whose name was given to a nearby dam, Falcon Dam. Rancho Viejo may be included as part of the Brownsville–Harlingen–Raymondville and the Matamoros–Brownsville metropolitan areas.
Rancho Viejo is also the name of the resort and country club that takes up much of the space in the town. It sprawls 1,400 acres (5.7 km2), mostly accounted for by the golf courses.
The median income for a household in the town was $64,038, and the median income for a family was $73,036. Males had a median income of $61,648 versus $34,750 for females. The per capita income for the town was $34,663. About 6.7% of families and 9.7% of the population were below the poverty line, including 9.9% of those under age 18 and 7.1% of those age 65 or over.