The Upper Las Virgenes Canyon Open Space Preserve is a large open space nature preserve owned and operated by the Santa Monica Mountains Conservancy spanning nearly 3,000 acres in the Simi Hills of western Los Angeles County and eastern Ventura County.
Originally part of Ahmanson Ranch, this area was sold by Seattle-based Washington Mutual to the Santa Monica Mountains Conservancy in late 2003 after lengthy issues concerning development in the chaparral shrub forest and oak savanna understory and overstory Plant communities. It was previously called Ahmanson Ranch Park. It sustained severe damage during the Woolsey Fire of 2018.
Wikipedia https://en.wikipedia.org/wiki/Upper_Las_Virgenes_Canyon_Open_Space_Preserve
Official Website http://lamountains.com/parks.asp?parkid=28
Coordinates 34°11'30.818" N -118°42'7.878" E