General Contractor El Rio

Early inhabitants of the area were the Chumash, a Native American tribe who continue to inhabit the area. The Chumash region extends from Point Conception to Santa Monica and back into the foothills as far as the Coast Range. One of their largest settlements was at nearby Saticoy, because of the bubbling springs that were found there.

On May 6, 1837, Juan M. Sanchez (1791–1873), a former Santa Barbara Presidio soldier, was granted the Rancho Santa Clara del Norte, which contained 13,989 acres (57 km²) of land extending from the Santa Clara River south to the northern boundary of present-day Camarillo, and from the present day 101 Freeway east to the west end of South Mountain. Sanchez and his wife, Ines Guevara de Sanchez (1794–1862), had their adobe home built below the western slope of South Mountain, within a heavy group of eucalyptus trees at the east end of present-day Rose Avenue, an avenue that was lined on both sides with tall eucalyptus trees.

The town was founded in 1875 and named New Jerusalem, California, by Simon Cohn (1852–1936), a Prussian Jewish merchant who built a general store at the location. The U.S. Post Office Department established New Jerusalem Post Office on July 26, 1882, and Cohn was appointed the first postmaster. The first one-room schoolhouse was opened in 1885. Santa Clara Catholic Church was founded the same year though services has been conducted since 1877. It was the first Catholic church to be built in Ventura County since the founding of Mission San Buenaventura 95 years earlier.