Three Forks is on Interstate 90, about 30 miles west of Bozeman. The drive takes under 30 minutes. Bozeman Yellowstone International Airport (BZN) has direct flights from most major US cities and is the practical gateway for the region.
There is no public transport to Three Forks. A car is essential — both for getting here and for reaching Missouri Headwaters State Park and the fishing access sites outside town. Most visitors use Bozeman as a base and make Three Forks a half-day or day trip, though the Sacagawea Hotel makes an overnight worthwhile.
From the north, US-287 connects from Helena (about 60 miles). From the south, Montana Highway 2 runs along the Jefferson River valley. The Madison River valley to the south is accessible via US-287 toward Ennis.