Andrés Pico -- rancher, military leader, and politician -- was born in San Diego in 1810. He was one of several sons of José María Pico and María Eustaquia López, who together were of Native American, Spanish and African mixed-race ancestry.
Andrés' older brother was Pío Pico, who served briefly as the last governor of Mexican-ruled California. While governor in 1845, Pio granted Andrés and Juan Manso a 9-year lease for the secularized Mission San Fernando Rey de España lands, which encompassed nearly the entire San Fernando Valley. Andrés was 35 and lived at the pueblo of Los Angeles. He raised cattle on the ranch and made the Mission his rancho-base.
In 1846, Pio needed money for the Mexican-American War effort, so he sold the secularized lands to Eulogio de Celis, excluding the Mission and its immediately adjacent lands. De Celis called the property Rancho ex-Mission San Fernando. Although de Celis returned to Spain, his descendants stayed in California.
On January 13, 1847, as the acting governor of Mexican Alta California (while his brother was in Mexico raising additional money for the fight against the United States), Andrés signed the Treaty of Cahuenga with the American commander Lieutenant-Colonel John C. Frémont, with whom he became friends.
This informal agreement ended the Mexican-American War battles in California and led to the Treaty of Guadalupe Hidalgo in 1848 which formally gave all of Mexico's territory to the United States.
In 1850, California became an American state, and Andrés and other residents became U.S. citizens with full legal and voting rights. He was elected to the California State Assembly from Los Angeles in 1851 and authored a bill to split California into two territories. Although the bill was approved and signed by the governor in 1859, the U.S. Congress never acted on it.
Meanwhile, in 1853, Pico acquired a half interest in the de Celis lands and became owner of the southern half of the San Fernando Valley.
In 1858, Pico was commissioned as a brigadier general in the California Militia.
In 1860, he was elected a California State Senator from Los Angeles.
By 1862, Andrés was in debt and sold his half-interest in the Rancho ex-Mission San Fernando to his brother Pío, who later sold it to Isaac Lankershim. Andrés retired in Los Angeles and died there on February 14, 1876. Andrés reportedly never married, but adopted two children, Romulo and Catarina, who married each other and lived at the Andres Pico Adobe.