The Clark Fork River Approximately 360 mi (579 km) long. The largest river by volume in Montana, it drains an extensive region of the Rocky Mountains in western Montana and northern Idaho in the watershed of the Columbia River.Rocky MountainswatershedColumbia River Flowing northwest through a long mountain valley and emptying into Lake Pend Oreille in northern Idaho.Lake Pend Oreille

The Kootenai River Is the uppermost major tributary of the Columbia River. Columbia River Flowing through British Columbia, Montana and Idaho.British ColumbiaMontana Idaho It one of the few rivers in North America which begins in Canada, enters the United States and then reenters Canada. North America

Flathead Lake Largest freshwater lake west of the Mississippi River. Located south of Kalispell. Popular resort lake for many Montanans and tourists.

The Jefferson River Is a tributary of the Missouri River, approximately 207 miles long.tributary Missouri River It is one of three rivers, along with the Madison and Gallatin that converge near Three Forks, Montana to form the Missouri.riversMadisonGallatinThree Forks, Montana Named by Lewis and Clark after President Thomas Jefferson.

The Madison River Is a tributary of the Missouri River, approximately 183 miles long.Missouri River It starts in Yellowstone Lake. It flows west then north through the mountains of southwestern Montana to join the Jefferson and Gallatin rivers at Three Forks to form the Missouri River. The river was named by Lewis and Clark in July 1805, for US Secretary of State James MadisonLewis and ClarkJames Madison

The Gallatin River Is a tributary of the Missouri River, approximately 120 mi. long.Missouri River It stars in Yellowstone It flows northwest through Gallatin National Forest, past Big Sky, Montana, and joins the Jefferson and Madison approximately 30 mi northwest of Bozeman.Gallatin National ForestBig Sky, MontanaBozeman The river was named by Lewis & Clark for Treasury Secretary Albert Gallatin. Albert Gallatin

The Sun River Is a tributary of the Missouri River in the Great Plains, approximately 130 mi. long.Missouri RiverGreat Plains The water of the river is used extensively for irrigation, through the Sun River Project of the United States Bureau of Reclamation. The irrigation area covers approximately 92,000 acresSun River ProjectUnited States Bureau of Reclamation

The Marias River Is a tributary of the Missouri River, approximately 210 mi. long.Missouri River The river was explored in 1805 by the Lewis and Clark expedition, who mistook it for the main branch of the Missouri until their subsequent discovery of the Great Falls of the Missouri near Great Falls, Montana. The river was named by Meriwether Lewis after his cousin, Maria Wood.1805Lewis and Clark expedition Great Falls of the MissouriGreat Falls, Montana Meriwether Lewis

The Milk River Is a tributary of the Missouri River, 729 mi. long.Missouri River The Milk is the northernmost major tributary of the Missouri. The Milk river was given its name by Captain Lewis, of the Lewis and Clark Expedition, who described the river in his journal:LewisLewis and Clark Expedition "the water of this river possesses a peculiar whiteness, being about the colour of a cup of tea with the admixture of a tablespoonfull of milk. from the colour of its water we called it Milk river."

The Missouri River Is a tributary of the Mississippi River and is the longest river in the United States. Mississippi RiverUnited States The Missouri begins at the confluence of the Madison, Jefferson, and Gallatin rivers in Montana (the “Three Forks”), and flows into the Mississippi north of St. Louis, Missouri.Madison JeffersonGallatinMontanaSt. Louis, Missouri At about 2,341 mi (3,725 km) in length, it drains approximately one-sixth of the North American continent.North American

The Musselshell River Is a tributary of the Missouri River, approximately 292 miles long, in central Montana.tributary Missouri River Montana The river flows across the Great Plains and is used extensively for irrigation. irrigation

The Yellowstone River Is a tributary of the Missouri, approximately 692 miMissouri Considered the principal tributary of the upper Missouri, the river and its tributaries drain a wide area stretching from the Rocky Mountains in the vicinity of the Yellowstone National Park across the mountains and high plains of southern Montana and northern Wyoming before flowing into the Missouri River near Buford, North Dakota.Rocky Mountains Yellowstone National Parkhigh plainsMontanaWyoming It is the longest undammed river in the lower 48 states.undammed

The Bighorn River Is a tributary of the Yellowstone, approximately 461 mi long.tributary Yellowstone At the border with Montana, the river turns northeast, and flows past the north end of the Bighorns, through the Crow Indian Reservation, where the Yellowtail Dam forms Bighorn Lake. Crow Indian Reservation Yellowtail Dam

The Tongue River Is a tributary of the Yellowstone, approximately 265 mi. long,tributary Yellowstone It forms the eastern boundary of the Northern Cheyenne Indian Reservation. Northern Cheyenne Indian Reservation It joins the Yellowstone near the town of Miles City.Miles City

The Powder River Is a tributary of the Yellowstone River, approximately 375 mi (603 km) long in the southeastern Montana. Yellowstone River Montana The Powder River was so named because the sand along a portion of its banks resembled gunpowder. Has been described as “a mile wide and an inch deep, too thin to plow and too thick to drink.”

Fort Peck Reservoir The fifth largest man- made lake in the U.S. Formed by the Fort Peck Dam. The dam and 134-mile long lake exist for the purposes of hydroelectric power generation, flood control, and water quality management.

Yellowstone National Park: Lower Yellowstone Falls on the Yellowstone River; Fishing Bridge on the Yellowstone River near Lake Yellowstone.

Approximate location of Yellowstone National Park

Location of Glacier National Park (see arrow above)

What to include on your Montana map: All counties & county seats; all 7 reservations Rivers: Clark Fork, Kootenai, Marias, Milk, Musselshell, Missouri, Yellowstone, Bighorn, Tongue, Powder, Jefferson, Madison, Gallatin, Sun; also Flathead Lake and Ft. Peck Reservoir Yellowstone & Glacier National Parks Mountains: Bitterroots, Bear’s Paw, Rockies, Continental Divide, Bighorns