Rocky Mountains Or Rockies Rocky Mountains or Rockies, great chain of rugged mountain ranges in western North America, extending from central New Mexico to northeastern British Columbia, a distance of about 3220 km (about 2000 mi). The Great Basin and the Rocky Mountain Trench, a valley running from northwestern Montana to northern British Columbia, border the Rockies on the east by the Great Plains and on the west. The Rocky Mountains form part of the Great, or Continental, Divide, which separates rivers draining into the Atlantic or Arctic oceans from those flowing toward the Pacific Ocean. The Arkansas, Colorado, Columbia, Missouri, Rio Grande, Saskatchewan, and Snake rivers rise in the Rockies. The Rockies may be divided into four principal sectionsSouthern, Central, Northern, and Canadian.
The Southern Rockies, which include the system’s broadest and highest regions, extend from central New Mexico, through Colorado, to the Great Divide, or Wyoming, Basin, in southern Wyoming. This section, which encompasses Rocky Mountain National Park, is composed chiefly of two northern-southern belts of mountain ranges with several basins, or parks, between the belts. The component parts include the Sanger de Crisco and Laramie mountains and the Front Range, in the east, and the San Juan Mountains and the Swatch and Park ranges, in the west. The Southern Rockies include the chain’s loftiest point, Mount Elbert (4399 m/14,433 ft high), in central Colorado. More than 50 other peaks of the Rockies rising above 4267 m (14,000 ft) are in Colorado; these include Longs Peak (4345 m/14,255 ft high) and Pikes Peak (4301 m/14,110 ft high). The Central Rockies are in northeastern Utah, western Wyoming, eastern Idaho, and southern Montana.
They encompass the Bighorn; Bear tooth, and Unite Mountains and the Absaroka, Wind River, Salt River, Teton, Snake River, and Wasatch ranges. The Unite Mountains are the only major portion of the Rockies that extends east west rather than north south. Among the peaks of the Central Rockies, which include Grand Eton and Yellowstone national parks, are Gannett Peak (4207 m/13,804 ft high), Grand Eton (4197 m/13,771 ft high), and Fremont Peak (4185 m/13,730 ft high). The Northern Rockies are in northern Idaho, western Montana, and northeastern Washington. They include the Saw tooth, Cabinet, Salmon River, and Clearwater Mountains and the Bitterroot Range.
The loftiest points in the section, which includes Glacier National Park, are Granite Peak (3901 m/12,799 ft high) and Borax Peak (3859 m/12,662 ft high). The Canadian Rockies, located in southwestern Alberta and eastern British Columbia, are composed of a relatively narrow belt of mountain ranges that terminates at the Lizard River lowland in northeastern British Columbia. The peaks of the section, which takes in Banff, Jasper, Kootenay, Waterton Lakes, and Yoho National Parks, include Mount Robson (3954 m/12,972 ft high), Mount Columbia (3747 m/12,294 ft high), and The Twins (3734 m/12,251 ft high). Slopes generally are very steep, and there are numerous glaciers. The Rocky Mountains are a geologically complex system with jagged peaks as well as almost flat-topped elevations. The Rockies were formed mainly by crustal uplifts in comparatively recent times, during the late Cretaceous and early Tertiary periods, and later were reshaped by glaciation during the Pleistocene Epoch. Today the Rockies receive moderate amounts of precipitation, most of which occurs in the winter.
Lower levels are covered chiefly by grassland, which gives way to extensive forests, principally of conifers. Above the woodland is a zone of grasses and scattered shrubs. Most peaks have little vegetation around the summit, and some have a year-round cap of snow and ice. The Rockies are sparsely populated for the most part and contain few cities. The principal economic.