The Sharp Fire was reported around noon and had burned about 60 acres by 10 p.m. The fire was not contained.
Mandatory evacuations were ordered for Mojave Scenic Drive, Buckthorn Road, East Canyon Drive, Mount Mahogany Road, Slippery Elm Road, and Lone Pine Canyon Road south of East Canyon. Seventy-five homes were affected.
An evacuation center was set up at Serrano High School at 9292 Sheep Creek Road in Phelan.
The fire is burning in steep terrain inaccessible by road, with firefighters hiking in to battle the flames. It was burning uphill and southbound, away from the town.
At least 300 firefighters were on scene. No injuries were reported.
The cause of the fire was under investigation.
Angeles National Forest is the lead firefighting agency and San Bernardino National Forest, San Bernardino County Fire and L.A. County Fire departments are assisting.