About 485 miles.
About 485 road miles from Helena, MT to Salt Lake City.
Salt Lake is closer the Pheonix than Helena.
About 646 miles.
Bozeman to Salt Lake is 410 miles.
The major cities in Montana are Billings (the largest) Helena (the capitol) Great Falls, Bozeman, Missoula, and Butte. Other well populated areas in Montana are the Kalispell/Whitefish area just outside Glacier National Park, Lewistown, Glasgow, Yellowstone National Park, and Flathead Lake.
Salt Lake City is the closest of those three. It is the second-closest state capital to Phoenix after Santa Fe, New Mexico.
It is 416 miles according to Google Maps.
The driving distance between Helena, MT and Salt Lake City, UT is approximately 485 miles. The driving time would be approximately 7 hours 30 minutes if you were to travel non-stop in good driving conditions. (The driving time does not take into consideration conditions which may extend trip time such as weather, road work and rush hour traffic in urban areas.)
Denver, Colorado Salt Lake City, Utah Carson City, Nevada Sacremento, California Salem, Oregon Oympia, Washington Helena, Montana Boise, Idaho Cheyenne, Wyoming
It is about 641 miles via Pocatello and Salt Lake City.
It is 240.68 miles from Silver Lake to Mackinac City.
Salt Lake City is 751.20 miles away from San Diego.