The Camarillo family of Ventura County traces its heritage back to Juan Camarillo, Sr. Born on May 27, 1812 in Mexico City to Luis and Maria Camarillo, Juan came to California with the Hijar-Padres Expedition in 1834. He married Martina H. Hernandez, the great-granddaughter of Jose Francisco Ortega, in 1840 or 1841 at the Santa Barbara Mission. They had 14 children, but only six survived: Adolfo, Juan, Adelaida, Aldegunda, Maria, and Arcadia. He arrived in Ventura in 1857, began acquiring land, and eventually came to own all of Rancho Calleguas, which he purchased from the Ruiz family. He died on December 4, 1880, and passed the land onto wife, Martina.

Martina owned the land, which was managed primarily by her son Adolfo, until her death on April 15, 1898. Adolfo, born on October 29, 1864 in Ventura, took over management of the family ranch at the age of 16, following the death of his father. He oversaw the ranch's transition from cattle to primarily lima beans, citrus, and walnuts. He married Isabella Menchaca in January 1888. Following a fire in 1892, Adolfo built the large-frame house that still sits on the ranch. He was a devout Catholic and served on numerous political bodies within the county. He also became famous for breeding white Arabian-Morgan horses that became known as Camarillo horses. He died on December 10, 1958 at the age of 94.

Juan E. Camarillo, Jr. was born on April 4, 1867 in Ventura. He never married. Juan was also known as a devout Catholic. He donated land for St. John's Seminary in Camarillo, and in 1913 he commissioned the construction of St. Mary Magdalene Memorial Chapel in Camarillo. He moved to Argentina in 1916, where he lived for around 15 years, before returning to Ventura. He died at his ranch house on August 21, 1936.

In 1908 there was a family dispute over Martina's will and the sisters filed a lawsuit. Arcadia testified in court that their mother had wanted to destroy her former will and write a new one in which all her children had equal rights to the ranch, but their brother Adolfo had tricked Martina and intentionally mistranslated the Spanish "hijos" to mean only sons rather than children. Arcadia alleged that she had been denied her rights and financially neglected by her brother when she had asked for help. Juan alleged that Arcadia had attempted to blackmail him for an "infamous crime." The courts settled in favor of Adolfo. For those interested, further resources on the family's history and contributions to local institutions are available at the MVC Research Library.