Firefighters gained ground on the Diamond Incident fire seven miles southeast of Greycliff Monday, increasing containment to 40 percent.
The Montana Department of Natural Resources and Conservation reported Tuesday that the fire remained at 650 acres.
The fire was first reported Saturday night in the Hobble Diamond ranch, according to DNRC. It sparked near two other fires, Hobble Diamond and Shank Basin, which were also lightning caused and were contained earlier this month.
At the Diamond Incident fire, 50 personnel are on site from multiple agencies, including the Bureau of Land Management, Forest Service, Montana DNRC, and local government from Sweetgrass, Yellowstone, Stillwater, and Musselshell counties.
Crews are expected to remain on scene to put out hot spots for the next few days. They are currently working to strengthen the perimeter, clear vegetation and create stronger fuel breaks.
Visit MT Fire Info for updated information on the fire.