Yucaipa (/ju??ka?p?/ ew-ky-p?) is a city located 10 miles (16 km) east of San Bernardino, in San Bernardino County, California,United States. The population was 51,367 at the 2010 census, up from 41,207 at the 2000 census. According to San Bernardino County, the projected population in 2012 is 58,187.
Prior to the Spanish conquest of the Americas and the arrival of European settlers from Mexico, the land of the Yucaipa Valley was occupied by the Serrano Indians for possibly 1,000 years.
Yucaipa Valley supported a large population of Serrano Indians. The fertile valley was watered by springs and creeks running out of the San Bernardino Mountains. The Serrano lived in this location most of the year, but would make excursions into the mountains to gather acorns and other food items during their harvest season. The Serrano name for the area was Yucaipat which meant "green valley." The Rancheria is marked by California Historical Landmark #620.