Three men died after the car they were in went off Highway 313 southwest of Hardin, traveled over an embankment and came to rest on its top in a ditch full of water.
The Montana Highway Patrol says the crash was reported at about 3:20 p.m. Tuesday, but Trooper Aaron Freivalds said it is not clear when it occurred.
Freivalds says the car was submerged and the crash site was hard to see from the road.
Freivalds told The Billings Gazette the victims were Native American and the Bureau of Indian Affairs is investigating the crash.