Rancho Calleguas was a 9,998-acre (40.46 km2) Mexican land grant in present-day Ventura County, California given in 1837 by Governor Juan Alvarado to José Pedro Ruiz.
José Pedro Ruiz married María Ygnacia Lugo, and was granted Rancho Calleguas in 1837.
With the cession of California to the United States following the Mexican-American War, the 1848 Treaty of Guadalupe Hidalgo provided that the land grants would be honored.
Successful in business, Juan Camarillo began to invest in land, including the purchase of Rancho Ojai in 1856.
Martina willed her entire interest in Rancho Calleguas to her sons, Adolfo (1864–1958) and Juan, Jr. (1867–1936).