The Santa Ana Valley is located in Orange County, California and is bisected by the Santa Ana River. The valley is home to most of Orange County’s central business districts. Cities such as Anaheim, Costa Mesa, Fullerton, Irvine, Orange, Santa Ana, and Yorba Linda are located in the Santa Ana Valley.
This valley was named Vallejo de Santa Ana in 1769 after the Gaspar de Portola expedition, of which Friar Junípero Serra was a part of, as well as Sargeant Jose Antonio Yorba, and José Manuel Nieto. The mission located closest to the Santa Ana Valley is Mission San Juan Capistrano, which was built east of the San Joaquin Hills in what is now the modern-day city of San Juan Capistrano.