The “Blacktail” fire, burning 11 miles east of Idaho Falls, near Ririe Reservoir, had burned about 1,782 acres of grass, brush and juniper fuels officials said.
The Bureau of Land Management said the fire began on July 22 and is expected to be contained by Saturday night and the fire out by Monday.
The cause of the fire is still under investigation.
There are about 100 fire personnel tending to the fire with four type 4 engines, three type 6 engines, the Snake River Hotshot crew, the Centennial Hand Crew, four bulldozers, two water tenders, one helicopter, two heavy air tankers, two single-engine air tankers, air attack, and a lead plane.
Prevention technician for the BLM Karen Roybal said there have been no reports of injury and there have been no road closures.
If all goes as planned, the BLM will scale back on personnel soon.