Crews worked to mop up hot spots and line a perimeter around the burn area.
The second-alarm Princeton Fire was reported shortly before 2:30 p.m. Saturday.
A northeast wind was pushing the fire toward the southwest. Nearby residents and businesses were told to shelter in place, according to the VCFD.
Air tankers and helicopters were deployed and about 180 firefighters from multiple agencies battled the blaze.
West Los Angeles Avenue from Madera Road in Simi Valley into Moorpark was closed. It was unclear for how long the stretch of road would be shut down.