The Cox's Well Fire near Craters of the Moon National Monument is 70 percent contained, the BLM said Wednesday morning.
The 8,064-acre fire is not close to any structures, but it is threatening sage grouse habitat, and resource advisers are on scene.
The Cox's Well Fire is burning 11 miles west of Springfield on Bureau of Land Management land.
Crews had hoped to contain the blaze by 7 a.m. Wednesday.
The East Idaho Interagency Fire Center said the fire as high growth potential and access to the fire is difficult to due the rough terrain and limited road access.
Six engines, an air attack platform, two helicopters, two dozers, two water tenders and two single-engine air tankers are at the scene.
The BLM said the fire was apparently caused by lightning.