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Summary Article: Rocky Mountains from The Hutchinson Unabridged Encyclopedia with Atlas and Weather Guide

Largest North American mountain system, extending for 4,800 km/3,000 mi from the Mexican plateau near Sante Fe, north through the west-central states of the USA, and through Canada to the Alaskan border. It forms part of the Continental Divide, which separates rivers draining into the Atlantic or Arctic oceans from those flowing toward the Pacific Ocean. To the east lie the Great Plains, and to the west, the plateaux separating the Rocky Mountains from parallel Pacific coast ranges. Mount Elbert is the highest peak, 4,400 m/14,433 ft. Some geographers consider the Yukon and Alaskan ranges as part of the system, making the highest point Mount McKinley (Denali) 6,194 m/20,320 ft, and its total length 5,150 km/3,219 mi.

Many large rivers rise in the Rocky Mountains, including the Missouri. Rocky Mountain National Park (1915) in Colorado has more than 107 named peaks over 3,350 m/10,000 ft. Because of the rugged terrain, the Rocky Mountains are sparsely populated. The mountains' chief economic asset is their minerals, including coal, petroleum, natural gas, copper, and gold. Lumbering is found in the northern Rockies, and cattle and sheep are raised. The Rocky Mountains have US and Canadian national parks, which attract many tourists.

Ranges The Rockies may be divided into four principal groups: the Canadian, and the Northern, Central, and Southern US groups. The Alaskan and Yukon ranges are sometimes included as a fifth and northernmost body of the chain.

The Canadian Rockies run 725 km/453 mi, from the US-Canadian border to the Liard River, and divide Alberta from British Columbia. It is composed of three belts: the main eastern range, the central Purcell and Selkirk mountains; and the Cariboo and Monashee mountains to the west

The US Rockies extend 1,950 km/1,219 mi, separated by river valleys into the Northern, Central and Southern sections. The Northern group runs 390 km/244 mi from the Canadian border to the Jefferson River, through Washington, Montana, and Idaho. Its chief ranges are the Lewis to the east, and the Bitterroot Range to the west.

The Central portion, extending 375 km/234 mi from the Yellowstone River to the Wyoming Basin, crosses Montana, Idaho, Wyoming and Utah. It includes five principal north–south elevations: the Windriver, Absaroka, Teton and Wasatch ranges, and the Beartooth and Bighorn mountains; and the system's only east–west range, the Uinta Mountains in Utah.

Lying mostly in Colorado, the Southern group is the highest and broadest of the system, running 690 km/431 mi from the Wyoming Basin to Santa Fe in New Mexico. It encompasses four main ranges, which form two north–south belts separated by basins; the Sangre de Cristo Mountains and Front Range to the east, and the San Juan Mountains and Park Range to the west.

If included in the chain, the Alaskan and Yukon belts constitute the highest part of the Rockies, incorporating the St Elias Mountains, near the Alaska–Yukon border, and the Wrangell and Alaska ranges.

Peaks Nearly 750 mountains exceed 3,050 m/10,000 ft in the Canadian Rockies; 700 lie in the main eastern range and 50 in the Selkirk and Purcell mountains. The loftiest peaks are Mount Robson, which rises to 3,954 m/12,972 ft, and Mount Columbia at 3,747 m/12,293 ft in the main range; Sir Sandford, 3,533 m/11,590 ft high, in the Selkirks; and Farnham, which reaches 3,457 m/11,342 ft m in the Purcell Mountains. Mount Sir Wilfrid Laurier in the Cariboo Mountains climbs to 3,582 m/11,750 ft.

The highest point in the Northern section of the US Rocky Mountains lies in the Lewis range, where Mount Cleveland attains 3,181 m/10,436 ft. Greatest elevations in the Central group are Granite Peak (3,901 m/12,799 ft) in the Beartooth Mountains; Cloud Peak (4,019 m/13,186 ft high) in the Bighorn range; Grand Teton (4,190 m/13,747 ft) in the Tetons; Gannett Peak (4,202 m/13,793 ft) in the Windriver Mountains; and Granite Peak (3,815 m/12,518 ft) in the Absaroka range. The Southern part of the chain is the highest, with 46 summits topping 4,270 m/14,000 ft. They include Mount Elbert, which dominates Park Range, with a height of 4,400 m/14,433 ft; Longs Peak, reaching 4,345 m/14,255 ft in Front Range; the 4,386 m/14,390 ft-high Blanca Peak, in the Sangre de Cristo Mountains; and in the San Juan Mountains, the Uncompahgre Peak at 4,360 m/14,304 ft.

Where they are included in the system, the Alaskan and Yukon mountains contain the greatest elevations. The St Elias Mountains, on the Yukon-Alaskan border, feature Mount Logan, the highest summit in Canada at 6,050/19,850 ft; St Elias which rises to 5,488 m/18,005 ft; and Fairweather, 4663 m/15,299 ft. Mount Blackburn climbs to 4,919 m/16,138 ft in the Wrangell range. With a height of 6,194 m/20,320 ft, Mount McKinley in the Alaska Range is the loftiest point in North America.

Geology In late Cretaceous times mountain building uplifted sedimentary beds on an ancient continental flow. This was the Larimide Revolution and resulted in the formation of the Rocky Mountains. The Rockies are in two parallel ranges trending north–south. The process of the formation of was accompanied by tectonic activity. In the south the ranges are mainly granitic; in the central area and Canada they are largely sedimentary and retain evidence of their original bedding. In some areas, the volcanic activity which accompanied mountain building has produced large batholiths (domes of igneous rock extending into the earth); one in central Idaho is 52,000 km/20,000 sq mi at 3,660 m/12,000 ft. Elsewhere, volcanic activity is still present, as in Yellowstone National Park in Wyoming with its 3,000 geysers and hot springs.

Glaciers, lakes, and rivers In the Canadian Rockies, the Columbian Icefield extends for 500 sq km/200 sq mi, straddling the Continental Divide on the Alberta–British Columbia border. Discounting the Yukon-Alaskan section, it is the largest glacier in the system. Further north, the glaciers of the southern Cariboo flow down to 1,375 m/4,511 ft.

Glaciers are vast in the Yukon–Alaska region. In the St Elias Mountains, the Malaspine Glacier stretches over an area of 3,885 sq km/1,494 sq mi. Other named glaciers include the Seward, and Logan in the St Elias range, and the Chisana and Nabesna in the Wrangell Mountains.

Lakes Louise, Moraine, O'Hara, Maligne, and others dot the eastern slopes of the Canadian Rockies. The largest natural lakes in the USA ranges occur in Wyoming. Yellowstone Lake, lies 2,357 m/7,732 ft above sea-level, in a basin to the west of the Absaroka Range; and Jackson Lake to the east of the Tetons.

Despite the large number of rivers which rise in the system, water supply remains a problem in many areas, especially in the drier south. Water-storage reservoirs in the Rockies were some of the first constructed in the USA, and most usable dam sites have now been exploited. Hydroelectric power is generated at numerous locations.

Principal rivers include the Saskatchewan, Athabasca, Fraser, Columbia, Snake, Peace, Missouri, Arkansas, Rio Grande, and Colorado.

Communications The Canadian Pacific Railway and Transcontinental Highway traverse the British Columbia–Alberta border through Kicking Horse Pass, 1,627 m/5,338 ft above sea-level; it is the highest point on the railroad. Continuing further east, Rogers Pass cuts through the Selkirk Mountains at an altitude 1,327 m/4,355 ft; a route subject to severe avalanches. The route across the Rockies for 300,000 emigrants in pre-railway times, from the 1840s to the 1860s, was the Oregon Trail. Between the southern and central Rockies it is only 2,135 m/7,000 ft and wagons could be hauled over without difficulty. The railway from Chicago to California takes this route. In the far north, the Alaska Highway was built across the mountains following the Liard River through the southern end of the Mackenzie Range.

Resources Copper, iron ore, silver, gold, lead, zinc, molybdenum, and uranium are mined, and a number of the mountain basins yield oil and natural gas. The region also contains large coal reserves. Lumbering and other forest products industries are form a major part of the economy in the northernmost sections of the Rockies. Livestock is reared in the Central and Southern sections.

Visitors are attracted to the region by some of the most spectacular scenery of the North American continent, and there are numerous facilities for recreation and mountain activities, including hiking, mountain climbing, horse-riding, and winter sports.

Preservation Much of the US Rockies is under federal control; national parks include Rocky Mountain and Mesa Verde in Colorado; Grand Teton and Yellowstone in Wyoming; and Glacier in Montana. The Canadian Rockies include the Banff, Jasper, Yoho, Glacier, Revelstoke, and Kootenay national parks. In Alaska, there are still areas of unexplored wilderness. The main environmental problems are despoliation and pollution caused by industrial activity and mineral exploitation; events such as the laying of the Alaskan oil-pipeline have highlighted these issues.

History The American Indian inhabitants of the Rockies were mainly nomadic hunters, the cliff-dwelling Anasazi, who inhabited Colorado until about 1300 AD, being the exception. Early Spanish explorers were probably the first Europeans to view the Rockies, but the French explorer Pierre Verendrye (1685–1749) made the first recorded sighting of the Bighorn range of Wyoming in 1738. The mountains remained a barrier to trade and travel until the Union Pacific railroad crossed them in 1870. The explorations of Lewis and Clark who were commissioned to find a land route in the late 18th century, and the 19th-century geologist John Wesley Powell, opened up the region.

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Rocky Mountains National Park

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Bow River

Canadian Pacific Railway

Lake Louise

Mount Moran, Wyoming

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