ci.simi-valley.ca.us Simi Valley is an incorporated city located in a valley of the same name in the southeast corner of Ventura County, California, bordering the San Fernando Valley of Los Angeles in the Greater Los Angeles Area. According to the United States Bureau of the Census, the city had a population of 124,237 in 2010 up from 111,351 in 2000. Simi Valley is the home of the Ronald Reagan Presidential Library, where the former president was laid to rest following his death in 2004. The city received media attention as the location of the 1992 trial and acquittal of four Los Angeles Police officers accused of assaulting Rodney King, triggering riots in Los Angeles and elsewhere. The town sits adjacent to the site of America's first significant nuclear accident, at the Santa Susana Field Laboratory in 1959. The city of Simi Valley is surrounded by the Santa Susana Mountain range and the Simi Hills, west of the San Fernando Valley and east of the Conejo Valley. It is largely a commuter bedroom community feeding the larger cities in Ventura County to the west and the Los Angeles area and the San Fernando Valley to the east. Simi Valley repeatedly appears on Safest Cities in America lists.