Chino Hills is a city located in the southwestern corner of San Bernardino County, California, United States. The city borders Los Angeles County on its northwest side, Orange County to its south and southwest, and Riverside County to its southeast.
After the Spanish founded Mission San Gabriel in 1771, the Chino Hills region was used extensively for grazing by mission cattle. During the Mexican Republic era, the hills were used as spillover grazing from such surrounding Mexican ranchos as Santa Ana del Chino and Rancho La Sierra (Yorba). After Mexico ceded California to the United States it was, and still is, a swamp and subject to flooding annually. Most historical dwellings were demolished in the rush to develop the modern city. A local state monument is present in the grass lawn area of the local fire department. Casa Colina, a well-known rehabilitation center now situated in Pomona California, began as a tubercular clinic in the Los Serranos sector.
This land was sold to Richard Gird, the founder of nearby Chino subdivision and from which the town of Chino sprung in 1910. With the building of the Carbon Canyon Mineral Springs in the modern-day Sleepy Hollow region of the city and the new Los Serranos Country Club in Los Serranos, Chino Hills, California, the area became a destination for both Los Angeles tourists and bootleggers during the prohibition because of its isolation. For the same reason, Sleepy Hollow became a destination for hippies and artists during the 1960s.