I'll have to double check but I am pretty sure it is 15 in MT. That was what it was when I was a kid many years ago. I don't know if they did it to coincide with when we could drive (which was 15). Now the kids have to drive with a family member adult for awhile. When I did it I passed my drivers test and drove 300 miles to my grandparents. Off subject. I should just look it up.
