COLSTRIP - The Richard Spring Fire south of Colstrip in Rosebud County was estimated at nearly 63,000 acres and again forced the closure of Highway 39 late Tuesday morning.
The Type 3 wildfire was first reported on Sunday afternoon on private land 10 miles south of Colstrip.
The fire has forced the closure of Highway 39 several times. The highway was briefly opened Tuesday morning to limited traffic before authorities announced it was closed again later in the morning.
The fire is now the largest active fire in the state and is nearing the size of the PF Fire in Big Horn County that burned 66,134 acres before it was fully contained.
There was no containment reported on the Richard Spring Fire as of Tuesday morning. There were 131 personnel working on the blaze.
The cause of the wildfire has not been determined.