BLM says the fire is about 300 acres in size and burning in dry grass and sagebrush.
Crews say the fire is burning towards Swan Falls Dam in a very steep, rocky area, making it more difficult to fight.
Fire officials say no structures are being threatened right now, but Celebration Park and some nearby campsites were evacuated as a precaution.
BLM says they are responding with 7 engines, 1 water tender, 1 bulldozer, 1 helicopter, and one single-engine air tanker, along with fire crews from the Melba Rural Fire Department.
Officials says they expect to contain the fire around midnight.