Robert Lambert, 61, of Missoula, is dead after the Ford pickup he was driving plunged down a steep embankment.
The crash occurred on Schwartz Creek Road, east of Missoula near Clinton, at about 7 p.m. Monday.
Montana Highway Patrol says alcohol was a factor in the crash, and Lambert was not wearing a seat belt.
Montana Highway Patrol said he ran off of the road, and when he tried to back up, the vehicle rolled down the embankment.
Lambert was pinned under the car and pronounced dead at the scene.