, California, a city in Los Angeles County. It is in the San Gabriel Valley, 10 miles (16 km) southeast of downtown Los Angeles. Pico Rivera is an industrial city that assembles automobiles and manufactures metal products and processed foods. A museum that was the mansion of the last Mexican governor of California is here. The first settlement was by the Spanish in 1784, but the city was not incorporated until 1958. It has the council-manager form of government.