The fire was reported near Naval Hospital Camp Pendleton around 1 p.m. and quickly grew to 1000 acres. As of 9:45 p.m., containment was reported at 15 percent.
Smoke was viewable from the 5 Freeway in Oceanside, Temecula and Fallbrook.
Naval Hospital Camp Pendleton officials were diverting their patients to local hospitals as a result of the close proximity fire but have since reopened.
Residents evacuated from O'Neill Heights were provided alternate housing on base.
Camp Pendleton firefighters were on scene with help from Cal Fire, air tankers, and a helicopter.