A rockslide blocked the road to Pictograph State Park just south of Billings on Tuesday afternoon.
It looks as if a large slab of east-facing Rimrocks fell, leaving large sandstone boulders in its wake.
No emergency crews or state or county road crews were on scene Wednesday evening.
The gate on Coburn Road about a mile from the entrance to the park and the rock slide location was set to close at its regular 5 p.m time.
No one appears to have been injured.