Montana

I

Introduction

Montana, state in the western United States, the northernmost of the Rocky Mountain states. Montana is called the Treasure State because of its mineral wealth. The name Montana comes from the Spanish word meaning “mountainous” and was first used when the area was designated a territory in 1864. Montana entered the Union on November 8, 1889, as the 41st state. Helena is the capital. Billings is the largest city.

Although many people consider Montana completely mountainous, two-thirds of the state is part of the Great Plains. From the majestic peaks of Glacier National Park in the northwest to the comparatively level terrain near the eastern border the Montana landscape is one of great beauty, an ever-changing panorama of forest and prairie, highland and broad valley.

Montana’s history has been turbulent. The region experienced an early and active fur-trading era. With the discovery of gold it developed a vigorous and wealthy mining frontier and later saw a brief but exciting period of the open-range cattle industry. Eventually, dryland and irrigated agriculture spread into many parts of the state. Today despite the arrival of urbanization and modern society, much of the old flavor of the frontier West survives in Montana.

II

Physical Geography

Montana is bounded on the north by the Canadian provinces of British Columbia, Alberta, and Saskatchewan; on the east by North Dakota and South Dakota; on the south by Wyoming and Idaho; and on the west by Idaho. Montana is the nation’s fourth largest state, covering 380,837 sq km (147,042 sq mi), including 3,859 sq km (1,490 sq mi) of inland waters. The land area of Montana is more than three times that of Pennsylvania and about the same as that of Iowa, Illinois, and Indiana combined. The state’s extreme dimensions are 517 km (321 mi) from north to south and 877 km (545 mi) from east to west. The mean elevation is 1,040 m (3,400 ft).

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A

Natural Regions

Included within Montana’s boundaries are parts of two of North America’s major physiographic provinces, or natural regions. First is the Rocky Mountains, of which there are two subdivisions in Montana, the Northern Rocky Mountains and the Middle Rocky Mountains. The second natural region, the Interior Plains, is represented in a section of the Great Plains lying in eastern Montana. The Rocky Mountains in Montana, which cover the state’s western third, extend in a belt about 300 km (about 200 mi) wide from the Canadian border to the Wyoming border. In several places east of this line isolated groups of low mountains rise above the general level of the plains.

Montana’s Northern Rocky Mountain province varies topographically. The majority of this spectacular natural region is classified as open mountains, a globally distinctive and very rare setting with high detached mountain ranges separated by broad, smooth-floored valleys. These valleys range from about 900 to 1,500 m (about 3,000 to 5,000 ft) above sea level and are ringed by mountains that rise to elevations of 2,400 to 3,000 m (8,000 to 10,000 ft). Important valleys in this region include the Flathead, Bitterroot, Deer Lodge, Helena (or Prickly Pear), Beaverhead, Big Hole, Madison, and Gallatin. The surrounding highlands include the Beaverhead Mountains, Mission Range, Tobacco Root Mountains, Bridger Range, Big Belt Mountains, and Crazy Mountains.

The two prongs of Montana’s Columbia Rockies, which include the highlands along the Montana-Idaho border from the Bitterroot Valley northward, and east of Flathead Lake, Glacier National Park, and the adjacent highlands on the south, contain classic mountain landscape. Here, individual ranges usually are closely spaced with narrow and restricted valleys. The Cabinet Mountains, Purcell Mountains, Whitefish, and Flathead ranges and the Lewis and Swan ranges are some of the landmark highlands within this rugged section of Montana’s Northern Rockies. Interestingly, this mountain-dominated region claims the state’s lowest elevation of 550 m (1,800 ft) above sea level, where the Kootenai River flows into Idaho.

The small section of the Middle Rocky Mountains in Montana consists of the high and rugged Absaroka and Beartooth ranges north of Yellowstone National Park. Within this province is Montana’s highest elevation, 3,901 m (12,799 ft), at Granite Peak.

Many Montana highlands were glaciated during the Pleistocene Epoch (2.5 million to 10,000 years ago). The sharpened alpine glacial landforms conspicuous in the crest areas of these mountains are best developed in Glacier National Park.

The eastern two-thirds of Montana is part of the Great Plains. This region, known as the Missouri Plateau, is divided into two segments, the glaciated section in the north and the unglaciated section in the south. Both sections are generally flat or gently rolling, but the glaciated north has numerous lakes while the unglaciated south is somewhat drier and smoother. The general elevation of the Great Plains decreases from about 1,200 m (about 4,000 ft) at the edge of the mountains in the west to about 600 m (about 2,000 ft) near the eastern boundary, although the descent is so gradual that it is scarcely noticeable. Rising above the plains surface are several prominent Rocky Mountain outliers, the Sweetgrass Hills, the Bear Paw Mountains, the Little Rockies, the Highwood Mountains, the Judith Mountains, and the Little Snowy and Big Snowy mountains.

Over thousands of years, most of the streams and rivers of eastern Montana have cut valleys below the level of the plains. Along the middle Missouri River and in the southeastern section, an irregular badland topography was cut by water and wind erosion.

B

Rivers and Lakes

Montana’s two main river systems are the Missouri River and its tributaries, which flow east to the Mississippi River, and tributaries of the Columbia River, which flow west into the Pacific Ocean.

Trending southward across the western part of Montana, the Continental Divide separates the state’s two major watersheds. West of this continental backbone are the Clark Fork and the Kootenai River, important tributaries of the Columbia River. The Clark Fork originates within Montana and has as its primary tributaries the Flathead, Blackfoot, and Bitterroot rivers. The Kootenai River rises in Canada and traverses a small area in northwestern Montana.

The Missouri and its major tributary, the Yellowstone River, are the principal rivers in eastern Montana. The Missouri begins at the confluence of the Gallatin, Madison, and Jefferson rivers, near the town of Three Forks. Other tributaries below Three Forks include the Sun, Teton, Marias, Smith, Judith, Musselshell, and Milk rivers. The Yellowstone rises south of Yellowstone National Park in Wyoming, flows north into Montana and diagonally across the southeastern part of the state before joining the Missouri in North Dakota just east of the state border. Main tributaries are the Clarks Fork of the Yellowstone, the Bighorn, the Tongue, and the Powder rivers, all of which also originate in Wyoming.

A tiny area of Montana is drained by the Belly and Saint Mary rivers, which, rising in Glacier National Park, flow northeast out of the state and into the Saskatchewan River in Canada. Their waters eventually reach Hudson Bay.

Montana has numerous lakes and reservoirs. Most of the natural lakes are in the mountains of the western third of the state. Flathead Lake, with an area of 495 sq km (191 sq mi), is Montana’s largest lake, and the largest natural freshwater lake in the contiguous states west of the Mississippi River.

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