The Simi Hills run east-west for approximately 26 miles and average about 7 miles in width. The area is an important wildlife corridor and open space linking the Santa Monica Mountains to the Santa Susana Mountains and beyond to the Topatopa and San Gabriel Mountains. The highest peak is Simi Peak rising to 2,403 feet.
The Simi Hills are located almost entirely in southeastern Ventura County with a small area located within the western San Fernando Valley section of Los Angeles County. The city of Simi Valley is located to the north, Thousand Oaks to the west, Agoura Hills, Oak Park, and Calabasas to the south, and West Hills, Woodland Hills, and Chatsworth to the far east. Bell Canyon and Bell Canyon Park are also located in the Simi Hills.
The Santa Susana Pass Historic Park is located where the Simi Hills meet the Santa Susana Mountains on the border between Ventura County and Los Angeles County. The Upper Las Virgenes Canyon Open Space Preserve, formerly known as Ahmanson Ranch is located in the Simi Hills in the far eastern end of Ventura County. Perez Peak is a 1,575 foot peak in the Upper Las Virgenes Canyon Open Space. Sage Ranch Park is located high in the northwestern Simi Hills.
China Flat is a 1,100 acre plateau and meadow in the northern Simi Hills located north of Oak Park and Agoura Hills in Ventura County, just below Simi Peak which is the highest point in the Simi Hills. The flat is located at about 2,000 feet above sea level and is protected within the Cheeseboro Canyon / Palo Comado Canyon Open Space park which is within the Santa Monica Mountains National Recreation Area. Trails reach China Flat from trailheads in the Conejo Valley, Calabasas, the San Fernando Valley, Simi Valley, and the Upper Las Virgenes Canyon Open Space Preserve. The trail to the summit of Simi Peak passes through China Flat. The name is derived from the fact that Chinese railroad workers built an encampment there in the 1890s when they were not permitted to own land or become citizens.
Roscoe-Valley Circle Park
Roscoe-Valley Circle Park is an undeveloped open space park that is ideal for hiking in the Simi Hills. The park is located just north of West Hills and south of Chatsworth and offers excellent views of the San Fernando Valley and surrounding hills.
Santa Susana Pass
The Santa Susana Pass is a mountain pass in the Simi Hills connecting Chatsworth and tile San Fernando Valley to Simi Valley, The pass forms an important wildlife corridor between the Simi Hills to the south and the Santa Susana Mountains to the north. The area contains many scenic sandstone formations and huge boulders that have provided the background for many films, The Santa Susana Pass is the location of the Santa Susana Pass Historic Park consisting of more than 680 acres of open space.
Bell Creek, also known as Escorpion Creek, is a 10 mile long tributary of the Los Angeles River that originates in the Simi Hills of Ventura County and the San Fernando Valley area of Los Angeles County.
Rancho Las Virgenes
Rancho Las Virgenes was the 17,760 acre Spanish land grant given in 1802 that included present day Oak Park, Agoura Hills, part of Westlake Village, and a portion of the Simi Hills and Santa Monica Mountains. The Reyes Adobe, a historical site, built in 1845, is located in Agoura Hills. It is the oldest structure remaining in the Rancho Las Virgenes.
Placerita Canyon State Park
Placerita Canyon Nature Center
Placerita Canyon State Park, in Los Angeles County, was created to preserve and protect the site of the first discovery of gold in California in 1842. Its location links the Angeles National Forest, the Santa Susana Mountains, the Simi Hills, and the Santa Monica Mountains. The 342 acre state park features a nature center with gardens, extensive hiking trails, picnic areas, a waterfall, and various educational programs. The park contains the "Oak of the Golden Dream" site of the first discovery of gold in California and the historic Walker Cabin built in 1920. the Placerita Canyon Nature Center is located at 19152 Placerita Canyon Road in Newhall. Placerita Canyon was home to the Tataviam People, also known as the Tataviam Indians for thousands of years before the area was claimed by Spain and later by Mexico. Wildlife includes coyotes, bobcats, black bears, mountain lions, deer, rabbits, fox, badgers, and skunks.