Rancho Sierra Vista is one of the last intact ranches from the first half of the twentieth century in the Santa Monica Mountains. The majority of the landscape is much as it was 100 years ago. The area is now owned by the Santa Monica Mountains National Recreation Area, a unit of the National Park System.Prehistory and European ContactOver 150 archeological sites have been found indicating both permanent and transient occupation of the area by Native Americans. In 2014, glass beads were found at a small site exposed by the Springs Fire. This find possibly indicates contact in the late 1700s during the initial period of Spanish colonial occupation.The first European land exploration of the area was the Portola Expedition of 1769-70. The horsemen portrayed in the Saddle Rock Ranch Pictographs in the heart of the Santa Monica Mountains are considered to be a representation of Portola's exploring party, and have been determined to be eligible as a National Historic Landmark. The expeditions led by Juan Bautista de Anza also travelled through the area, first in 1774 and then again in 1776. The Juan Bautista de Anza National Historic Trail passes through Rancho Sierra Vista.Rancho period, 1802–1870sRancho Las Virgenes, 1802Rancho Las Virgenes was a 17,760 acre land grant given to Miguel Ortega but was abandoned after his death in 1809. Nemecio Domínguez and Domingo Carrillo received a Mexican grant in 1834. The lands of the Rancho Las Vírgenes included present day Agoura Hills, Oak Park, and Westlake Village and part of the Santa Monica Mountains.
