Watsonville, city (1990 pop. 31,099), Santa Cruz co., W Calif., on the Pajaro River near Monterey Bay; founded 1852, inc. 1868. It is a trade and processing center for vegetables, fruits, berries, and flowers. Other industries include petroleum refining, granite quarrying, and the manufacture of aluminum products. Watsonville's population more than doubled in the late 20th cent. Nearby are beach and mountain resorts and several state parks.