The 2,848 acres (1,153 ha) Santa Susana Field Laboratory located in the Simi Hills, was used for the development of pioneering nuclear reactors and rocket engines beginning in 1948.
The site was operated by Atomics International and Rocketdyne (originally both divisions of the North American Aviation company).
The city of Simi Valley is surrounded by the Santa Susana Mountain range and the Simi Hills, west of the San Fernando Valley, and northeast of the Conejo Valley.
It is largely a commuter bedroom community, feeding the cities in the Los Angeles area and the San Fernando Valley to the east, and cities in Ventura County to the west.
The city sits next to Thousand Oaks, Moorpark, and Los Angeles.
The city's 2014 population has been estimated at 126,871, up from 111,351 in 2000.
Other areas containing Chumash Native American pictographs in the Simi Hills are for instance by Lake Manor and Chatsworth.
Simi Adobe-Strathearn House was the headquarters of Rancho Simi, one of the largest land grants in Alta California by Spain. The first Europeans to visit Simi Valley were members of the Spanish Portolá expedition (1769–1770), the first European land entry and exploration of the present-day state of California.
The youth camp/home facility is based on an older larger one in Boys Town, Nebraska.
in the eponymous valley, is in the southeast corner of Ventura County, California, United States.
30 miles (48 km) from Downtown Los Angeles, Simi Valley is part of the Greater Los Angeles Area.
It is now a California Historical Landmark and on the U. The expedition traversed the valley on January 13–14, 1770, traveling from Conejo Valley to San Fernando Valley.
They camped near a native village in the valley on the 14th.) Spanish land grant in eastern Ventura and western Los Angeles counties given in 1795 to Francisco Javier Pico and his two brothers, Patricio Pico and Miguel Pico by Governor Diego de Borica.