Riverside County was formed from portions of San Bernardino and San Diego counties in 1893. Once predominantly an agriculture industry, Riverside County has seen many transformations with the additions of other businesses such as commerce, manufacturing, transportation, military, education and tourism. Between 1980 and 1990, Riverside was the fastest growing county in California, and is currently the fourth largest county in the state.
Today, the 42nd District encompasses the western edge of Riverside County including the cities of Eastvale, Norco, Corona, Lake Elsinore, Wildomar, Canyon Lake, Menifee, Murrieta and a portion of Temecula. The district also includes the unincorporated ares of El Sobrante, Woodcrest, Temescal Valley, Lakeview, Nuevo, Homeland, Winchester, and Aguanga.