Three Forks, located 30 miles northwest of Bozeman, lies at the confluence of the Jefferson, Madison and Gallatin Rivers, forming the headwaters of the Missouri River. There are 12 miles of paved trails in the Headwaters Trail System, winding around ponds and old growth cottonwood trees, with views of the surrounding mountains and grasslands, leading to the actual start of the Missouri River at Headwaters State Park.  

One popular run is the ~6 miles from Three Forks to Headwaters State Park, using the path along Frontage Rd. and then heading north. At Headwaters, there are additional spur trails and a 1.5-mile trail leading to the Headwaters.

Another option from Three Forks is to head west toward the Jefferson River, ~2 miles.