Saturday was one of the deadliest days ever on U.S. Highway 93 north and south of Missoula.
Four people died in two separate traffic accidents during the day, one near Hamilton and a triple fatality near Arlee.
According to the Montana Highway Patrol, three people died around 9 p.m. when a northbound 2005 Hyundai drifted into the southbound lane and crashed head-on into a Pontiac.
The driver of the Hyundai, 19-year-old Trevor Olson of Missoula, was killed, along with his passenger and cousin, 14-year-old Tanner Olson, also of Missoula. Neither of the teenagers were wearing seatbelts at the time of the crash.
The driver of the Pontiac, a 22-year-old male from Arlee, was injured in the accident. His 21-year-old female passenger, who was not wearing a seatbelt, was killed.
The other passengers in the Pontiac, a 4-year-old boy and an infant, were also injured; they too were not wearing seatbelts at the time of the accident.
The second deadly crash happened around 6:50 a.m. Saturday near Hamilton, when a 53-year-old Sheridan, Wyo., man lost control of his pickup truck.
The driver, who was headed north, overcorrected and slammed head-on into another pickup truck in the southbound lane.
The Wyoming man, who was not wearing his seatbelt, died in the crash. The 55-year-old Missoula driver of the second truck was wearing his seatbelt, and survived with injuries.
The road was dry at the time of the accident. Neither alcohol nor speed were factors in the crash, according to the Highway Patrol.
Names of the other victims will be released following family notification. Both accidents are under investigation.