Overview
Gallatin County only has a handful of major travel routes in and out of the County. Interstate 90 runs East and West across the Gallatin Valley with US 191 running North and South from Belgrade to Big Sky and West Yellowstone. A couple smaller highways connect to neighboring counties.
Gallatin Valley
Much of the traffic in the Gallatin Valley moves along Interstate 90 between Three Forks, Manhattan, Belgrade and Bozeman. Traffic moving towards Big Sky all goes through Four Corners on either Jackrabbit from Belgrade or Huffine from Bozeman. These are all four lane roads until you head South of Four Corners.
Big Sky
Access to Big Sky is solely via US 191 from Four Corners in the North or West Yellowstone in the South. This is a two lane road with congested traffic that often moves slowly. There are very few passing opportunities, so plan to take your time. Most of the route in the mountains does not have cellular coverage. All regular access to the Big Sky area is on US 191, there is a private road West to Ennis that is available in emergencies.
With the large volume of visitors, and limited egress, evacuation is a large and complicated concern of the Big Sky community. While evacuation is not the answer to every situation, it is important for visitors to have a basic understanding of the community in order to understand emergency directions from officials. We do encourage visitors to Big Sky to opt into Big Sky Emergency Notifications for while they are visiting.
West Yellowstone
While at the Southern end of the County, West Yellowstone is accessed from several routes. US 20 runs from Idaho in the West through West Yellowstone and continues East into Yellowstone National Park. US 191 runs to the North towards Big Sky and Bozeman, as well as you can take US 287 West towards Ennis on the North side of Hebgen Lake. Cell phone service largely disappears North of the Hebgen Basin and to the East when you enter Yellowstone National Park.
