Where Does the Missouri River End in Montana?

The Missouri River does not end in Montana. It flows through Montana for ~700 miles (from its Three Forks origin near Bozeman to the North Dakota border), then continues through North Dakota, South Dakota, Nebraska, Iowa, Kansas, and Missouri before joining the Mississippi River near St. Louis, Missouri—over 1,600 miles downstream from the Montana border.

In Montana, key points:

• Headwaters: Confluence of Jefferson, Madison, Gallatin at Three Forks (4,000 ft).
• Canyon Ferry, Hauser, Holter Lakes (dams near Helena).
• Great Falls (five waterfalls; 1805 portage).
• Fort Peck Lake (massive reservoir, 134 mi long).
• Exit: Crosses into ND near Williston.