The fire was reported shortly before noon near Hathaway Canyon and Morongo roads. The fire quickly spread to 1,500 acres by Sunday night.
According to San Bernardino National Forest officials, the fire was burning towards San Gorgonio Wilderness, but no evacuations were in place.
The Hathaway fire was 15 percent contained by 11 p.m., and no structures were threatened.
Fire officials said 400 firefighters were battling the fire. There was no word on the cause of the blaze.