Officials with the Beaverhead-Deerlodge National Forest say a Thursday grass fire south of Dillon appears to be human caused.
The Hanneberry Cabin fire burned about 31 acres along Interstate 15 about 17 miles southwest of Dillon. The fire is now reported at 95 percent contained.
Around 45 firefighters and two helicopters helped get the fire under control. Friday morning seven people and three engines remained to mop up.
The fire had prompted Union Pacific Railroad to halt rail traffic in the area, it has since resumed.
The fire remains under investigation.
Update: Officials downgraded containment to 95 percent after a morning update but say is should be fully contained by Friday afternoon.