Fire crews were able to contain the fire at around 7 a.m. Saturday morning, but not before it grew to more than 6,000 acres and burned seven outbuildings in the town of Mayfield.
No one was hurt in the blaze. It was human-caused, said Mallory Eils, a BLM spokeswoman.
The fire started Friday evening about 30 miles southeast of Boise. Fueled by sage and grass, it spread quickly through the night.
Firefighters from the Bureau of Land Management and the Mountain Home Fire Department joined forces to fight the blaze, said Eils.