This historic park, located in Los Angeles County where the Simi Hills meet the Santa Susana Mountains, is rich in natural, historical and cultural significance. Here in the western part of the Transverse Ranges, the land is dominated by high, narrow ridges and deep canyons covered with an abundant variety of plant life. The park offers panoramic views of the rugged natural landscape as a striking contrast to the developed communities nearby. May through November is usually dry. Cold, wet winters can send torrents of water over the bedrock. Rarely, heavy rains can cause flash floods in arid canyons. The park is open daily, 8am to sunset.
Wade S. on Browns Canyon to Oat Mountain
Road to the peak is fenced off with "No Trespassing" signs near the top, so the actual peak is unreachable. Path crosses property marked as private at least once. Ranger told me it's OK to walk the road but not to wander off it.
Ed S. on Old Stagecoach Road
Hiked from the bottom trailhead where Valley Circle, Lassen, and Baden cross, to the top trailhead on Lilac Lane. At the top you can see the San Fernando and Simi Valleys. The historical marker is along the trail at (34.261553,-118.628923). A great family hike, but 650 feet of elevation change is not for out-of-condition hikers.
I finally found the Stagecoach plaque! There is another trail head on Andora Ave. for Santa Susana Pass State Historic Park. There are trail maps but the plaque is not marked on the paper map. I used this existing trail map on this app and just started walking making my best guesses until my hike intersected the app's trail. Awesome view!