The Butte-Silver Bow coroner identified the girl killed in a Thursday crash as 15-year-old Kelsi Stratford.
Montana Highway Patrol says the crash happened on Highway 2 south of Butte near Thompson Park at about 4 p.m. Thursday.
Stratford was driving a pickup truck westbound when it crossed the eastbound lane and went airborne over an embankment.
Troopers say while in the air, the vehicle spun nearly around, landing on the front left side of the truck and rolled before coming to a stop on its roof.
It burst into flames upon impact and remained on fire until firefighters arrived on scene to put it out.
MHP dispatch says the driver was not ejected and was pronounced dead on scene.
"The body was taken to the crime lab last night," said Undersheriff George Skuletich. "We also have some DNA samples, that we have at the crime lab or bringing down to the crime lab, we should know the DNA test results in about a week."
Investigators say speed was a factor. It is unknown if alcohol was involved.
"We're going to map the crash scene which will tell us," said Montana Highway Patrol Trooper Ken Klapan. "We will be able to calculate how far the vehicle went."