<Li> the Firehole River, originating at Yellowstone National Park's Madison Lake, joins with the Gibbon to form the Madison River, and </Li> <Li> rising out of Gallatin Lake, also in the national park, flows the Gallatin River </Li> <P> The Missouri River officially starts at the confluence of the Jefferson and Madison in Missouri Headwaters State Park near Three Forks, Montana, and is joined by the Gallatin a mile (1.6 km) downstream . The Missouri then passes through Canyon Ferry Lake, a reservoir west of the Big Belt Mountains . Issuing from the mountains near Cascade, the river flows northeast to the city of Great Falls, where it drops over the Great Falls of the Missouri, a series of five substantial waterfalls . It then winds east through a scenic region of canyons and badlands known as the Missouri Breaks, receiving the Marias River from the west then widening into the Fort Peck Lake reservoir a few miles above the confluence with the Musselshell River . Farther on, the river passes through the Fort Peck Dam, and immediately downstream, the Milk River joins from the north . </P> <P> Flowing eastwards through the plains of eastern Montana, the Missouri receives the Poplar River from the north before crossing into North Dakota where the Yellowstone River, its greatest tributary by volume, joins from the southwest . At the confluence, the Yellowstone is actually the larger river . The Missouri then meanders east past Williston and into Lake Sakakawea, the reservoir formed by Garrison Dam . Below the dam the Missouri receives the Knife River from the west and flows south to Bismarck, the capital of North Dakota, where the Heart River joins from the west . It slows into the Lake Oahe reservoir just before the Cannonball River confluence . While it continues south, eventually reaching Oahe Dam in South Dakota, the Grand, Moreau and Cheyenne Rivers all join the Missouri from the west . </P>

Where are the headwaters of the missouri river located