Where does the Montana Trail 406 start?

The eastern terminus of the MT406 is located at the Fort Union parking area, at the border of North Dakota and Montana on the Missouri River.

The western terminus of the trail is located at the Idaho/Montana border along the MT406/Pacific Northwest Trail in the Kootenai National Forest.

The approximate midpoint of the MT406 is near the city of Emigrant and the geological point where the trail transforms from mountains to prairie landscapes is at Fort Benton.