Flames tore through the western part of Camp Pendleton and moved toward San Clemente on Wednesday, growing to 250 to 300 acres.
The fire was reported at 10 to 15 acres about 6:15 p.m. near San Mateo Campground along Cristianitos Road, according to Camp Pendleton.
Officials said the blaze, dubbed the Cristianitos fire, was heading away from the base and was just east of the Richard T. Steed Memorial Park, a recreation area next to a cluster of businesses and a golf course.
By 10 p.m., the Orange County Fire Authority said the forward progression had stopped on all sides except the northern flank of the fire.
Earlier in the evening, airborne crews rushed to put a line between the flames and homes north of Cristianitos Road in San Clemente.
No evacuations were ordered, according to the Fire Authority. It's unclear what caused the fire.
U.S. Forest Service was providing its night-flying helicopter to assist in the firefight.
This article will be updated as more information becomes available.