Missouri Headwaters State Park is located near Three Forks, Mt. This is where Sacagawea was taken by another tribe when she was 12 years old. She returned here with the Lewis and Clark expedition in 1805. This is the location where the Jefferson, Madison, and Gallitan rivers meet the Missouri River. Not much to see, but if you are interested in history, a good place to visit.
On the strip of land across the river is the location where Sacagawea was taken.