Montana Geography (Pg. 2)
East and north of this transition zone are expansive sparsely populated Northern Plains, with rolling tableland prairies, “island” mountain ranges, and scenic badlands extending into the Dakotas, Alberta, Saskatchewan, and Wyoming. The isolated island ranges east of the Divide include the Castle Mountains, Crazy Mountains, Little Belt Mountains, Snowy Mountains, Sweet Grass Hills, Bull Mountains. The Pryor Mountains South of Billings and, in the southeastern corner of the state near Ekalaka, the Long Pines and Short Pines.
The area east of the divide in the north-central portion of the state is known for the dramatic Missouri Breaks and other significant rock formations. Three stately buttes south of Great Falls are familiar landmarks. These buttes, Square Butte, Shaw Butte, and Crown Butte, are made of igneous rock, which is dense and has withstood weathering for many years. The underlying surface consists of shale. Many areas around these buttes are covered with clay surface soils. These soils have been derived from the weathering of the Colorado Formation. Farther east, areas such as Makoshika State Park near Glendive, and Medicine Rocks State Park near Ekalaka also highlight some of the most scenic badlands regions in the state.
Montana also contains a number of rivers, many of which are known for “blue-ribbon” trout fishing, but which also provide most of the water needed by residents of the state, as well as being a source of hydropower. Montana is the only state in the union whose rivers form parts of three major North American watersheds: The Pacific Ocean, the Gulf of Mexico, and Hudson Bay which are divided atop Triple Divide Peak in Glacier National Park.
West of the divide, the Clark Fork of the Columbia (not to be confused with the Clarks Fork of the Yellowstone River) rises in the Rocky Mountains near Butte and flows northwest to Missoula. There it is joined by the Blackfoot River and Bitterroot River and further downstream by the Flathead River before entering Idaho near Lake Pend Oreille, becoming part of the Columbia River, which flows to the Pacific Ocean. The Clark Fork discharges the greatest volume of water of any river exiting the state. TheFlathead River and Kootenai River also drain major portions of the western half of the state.
East of the divide, the Missouri River, formed by the confluence of the Jefferson, Madison, and Gallatin rivers, crosses the central part of the state, flows through theMissouri breaks and enters North Dakota. The Yellowstone River rises in Yellowstone Park in Wyoming, flows north to Livingston, Montana, where it then turns east and flows across the state until it joins the Missouri River a few miles east of the North Dakota boundary. The Yellowstone River is the longest undammed, free-flowing river in North America. Other major Montana tributaries of the Missouri include the Milk, Marias, Tongue, and Musselshell Rivers. Montana also claims the disputed title of possessing the “world’s shortest river,” the Roe River, just outside Great Falls, Montana. These rivers ultimately join the Mississippi River and flow into the Gulf of Mexico.
