The Lodgepole Fire is creeping closer to Challis with flames five miles from town. The fire is now burning more than 5,000 acres.
Hundreds of crew members are coming in to help.
Almost 500 firefighters were camped out near the Challis Community Center on Wednesday.
The fire is 0 percent contained, but Incident Commander Marty Addell said he has reason to believe that will soon change before the fire makes it to town.
"We're looking … really good, actually, because of the transition of fuels from the timber component down to the sage brush component,” he said.
Although a lot of Idaho's wildfires were sparked by lightning, the cause of this fire is still under investigation.