City (pop., 2000: 328,014), southwestern California, U.S. Lying on the plain of the Santa Ana River 25 mi (40 km) southeast of Los Angeles, it was founded by German immigrants in 1857 as a cooperative agricultural community.
After 1950 its citrus groves and vineyards had all but disappeared in the Los Angeles-Orange Co. urban-industrial expansion. Walt Disney 's first amusement park, Disneyland, opened there in 1955. Today it is a prominent convention site.