Rancho Viejo is located in
Cameron County on US 77/83 just north of the
Brownsville-Harlingen-San Benito, Texas metropolitan area.
By 1978 a community had developed around the Rancho Viejo Country Club. In 1980 the community voted 96 to 32 to incorporate. Its population at that time consisted of residents of the country club and included mostly wealthy retirees and professionals. In 1983 the estimated population of Rancho Viejo was 275; it increased to 750 by 1986. The population was 893 in 1990.
Around that time the community regularly experienced an estimated 30 percent population increase each winter, when "Winter Texans"-residents of colder northern climates-made Rancho Viejo their home. Another population surge was seen each summer, when Mexican nationals visited their summer homes at the resort.
Reportedly the population of Rancho Viejo had reached about 1,200 by 1992.