For a brief time, its postal address was known as Simiopolis, though it was soon shortened again to Simi by 1910.
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.
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.
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.