Andrés'brother, Pío Pico was the last Mexican Governor, who in 1848 signed the Treaty of Guadalupe Hidalgo formally ceding all of Mexico's Alta California territory to the United States.
Andrés'brother, Pío Pico was the last Mexican Governor. Gen Andrés Pico was one of the signatories of the Treaty of Guadalupe Hidalgo, in 1848 formally ceding all of Mexico's Alta California territory to the United States.