No one was hurt and no structures burned, however some homes were put on an evacuation advisory.
Fire investigators believe the fire was caused by someone in the area. they're asking the public for help.
Sky Harbour Road at Sulphur Springs Road remains closed to nonresidents, as firefighters work to put out hot spots.
The fire started along the San Joaquin River Trail.
Anyone who saw anything suspicious in that area Tuesday afternoon should call Cal-Fire investigators.