Petaluma (pĕtəlōˈmə) [key], city (1990 pop. 43,184), Sonoma co., W Calif.; inc. 1858. Founded in 1833 by a colony of Mexicans, Petaluma is a former major poultry and egg center that has grown into a full-fledged suburb since 1970. Its population has increased accordingly. Local industries produce fabricated metal products, baked goods, dairy products, and telecommunications products among others.