Rocky Mountains

Rocky Mountain National Park (photo courtesy of NPS)
Rocky Mountain National Park (photo courtesy of NPS)

The Rocky Mountains, often called the Rockies, are a broad mountain range in western North America. The Rocky Mountains stretch more than 3000 miles (4800 km) from British Columbia to New Mexico, extending through Canada and much of the breadth of the contiguous United States. The highest peak is Mount Elbert, in Colorado, which is 14,440 feet (4401 m) above sea level. Mount Robson (12,972 feet/3954 m) is the highest peak in the Canadian Rockies. The Rocky Mountain System is a United States physiographic region.


Geography and geology

The Rocky Mountains are commonly defined to stretch from the Liard River in British Columbia, down to the Rio Grande in New Mexico. The mountains can also be considered to run to Alaska or Mexico, but usually those mountains are considered to be part of the entire American cordillera, rather than part of the Rockies.

The younger ranges of the Rocky Mountains uplifted during the late Cretaceous period (140 million-65 million years ago), although some portions of the southern mountains date from uplifts during the Precambrian (3,980 million-600 million years ago). The mountains' geology is a complex of igneous and metamorphic rock; younger sedimentary rock occurs along the margins of the southern Rocky Mountains, and volcanic rock from the Tertiary (65 million-1.8 million years ago) occurs in the San Juan Mountains and in other areas. Millennia of severe erosion in the Wyoming Basin transformed intermountain basins into a relatively flat terrain. The Tetons and other north-central ranges are magnificent granitic intrusions of folded and faulted rocks of Paleozoic and Mesozoic age (Peterson 1986; Knight 1994).

Periods of glaciation occurred from the Pleistocene Epoch (1.8 million-70,000 years ago) to the Holocene Epoch (fewer than 11,000 years ago). Recent episodes included the Bull Lake Glaciation that began about 150,000 years ago and the Pinedale Glaciation that probably remained at full glaciation until 15,000-20,000 years ago (Pierce 1979). Ninety percent of Yellowstone National Park was covered by ice during the Pinedale Glaciation (Knight 1994). The "little ice age" was a period of glacial advance that lasted a few centuries from about 1550 to 1860. For example, the Agassiz and Jackson glaciers in Glacier National Park reached their most forward positions about 1860 during the little ice age (Grove 1990).

Water in its many forms sculpted the present Rocky Mountain landscape (Athearn 1960). Runoff and snowmelt from the peaks feed Rocky Mountain rivers and lakes with the water supply for one-quarter of the United States. The rivers that flow from the Rocky Mountains eventually drain into three of the world's five Oceans: the Atlantic Ocean, the Pacific Ocean, and the Arctic Ocean. These rivers include:

Missing image
Map showing approximate location of the Rocky Mountains.

Human History

Since the last great Ice Age, the Rocky Mountains were a sacred home first to Paleo-Indians and then to the Native American tribes of the Apache, Arapaho, Bannock, Blackfoot, Cheyenne, Crow. Flathead, Shoshoni, Sioux, Ute, and others (Johnson 1994). Paleo-Indians hunted the now-extinct mammoth and ancient bison (an animal 20% larger than modern bison) in the foothills and valleys of the mountains. Like the modern tribes that followed them, Paleo-Indians probably migrated to the plains in fall and winter for bison and to the mountains in spring and summer for fish, deer, elk, roots, and berries. In Colorado, along the crest of the Continental Divide, rock walls that Native Americans built for driving game date back 5,400-5,800 years (Buchholtz 1983). A growing body of scientific evidence indicates that Native Americans had significant effects on mammal populations by hunting and on vegetation patterns through deliberate burning (Kay 1994).

Recent human history of the Rocky Mountains is one of more rapid change (Lavender 1975; Knight 1994). The Spanish explorer Francisco Vsquez de Coronado--with a group of soldiers, missionaries, and African slaves--marched into the Rocky Mountain region from the south in 1540. The introduction of the horse, metal tools, rifles, new diseases, and different cultures profoundly changed the Native American cultures. Native American populations were extirpated from most of their historical ranges by disease, warfare, habitat loss (eradication of the bison), and continued assaults on their culture.

The Lewis and Clark expedition (1804-1806) was the first scientific reconnaissance of the Rocky Mountains. Specimens were collected for contemporary botanists, zoologists, and geologists (Jackson 1962). The expedition was said to have paved the way to (and through) the Rocky Mountains for European-Americans from the East, although Lewis and Clark met at least 11 European-American mountain men during their travels.

Mountain men, primarily French, Spanish, and American fur traders and explorers, roamed the Rocky Mountains from 1800 to 1850. The more famous of these include William Henry Ashley, Jim Bridger, Kit Carson, John Colter, Thomas Fitzpatrick, Andrew Henry, and Jedediah Smith. On July 24, 1832, Benjamin Bonneville led the first wagon train across the Rocky Mountains by using Wyoming's South Pass.

The Mormons began to settle near the Great Salt Lake in 1847. In 1859, gold was discovered near Cripple Creek, Colorado, and the regional economy of the Rocky Mountains was changed forever. The transcontinental railroad was completed in 1869, and Yellowstone National Park was established in 1872. While settlers filled the valleys and mining towns, conservation and preservation ethics began to take hold. President Harrison established several forest reserves in the Rocky Mountains in 1891-1892. In 1905, President Theodore Roosevelt extended the Medicine Bow Forest Reserve to include the area now managed as Rocky Mountain National Park (Buchholtz 1983). Economic development began to center on mining, forestry, agriculture, and recreation, as well as on the service industries that support them (Lavender 1975). Tents and camps became ranches and farms, forts and train stations became towns, and some towns became cities.

Industry and Development

Economic resources of the Rocky Mountains are varied and abundant. Minerals found in the Rocky Mountains include significant deposits of copper, gold, lead, molybdenum, silver, tungsten, and zinc. The Wyoming Basin and several smaller areas contain significant reserves of coal, natural gas, oil shale, and petroleum. For example, the Climax mine, located near Leadville, Colorado, was the largest producer of Molybdenum in the world. Molybdenum is used in heat-resistant steel in such things as cars and planes. The Climax mine employed over 3,000 workers. The Coeur d’Alene mine of northern Idaho produces silver, lead, and zinc. Canada's largest coal mines are in the Crowsnest Coal Field near Sparwood, British Columbia and Elkford, British Columbia; additional coal mines exist near Hinton, Alberta.

Abandoned mines with their wakes of mine tailings and toxic wastes dot the Rocky Mountain landscape. Eighty years of zinc mining profoundly polluted the river and bank near Eagle River in north-central Colorado. High concentrations of the metal carried by spring runoff harmed algae, moss, and trout populations. An economic analysis of mining effects at this site revealed declining property values, degraded water quality, and the loss of recreational opportunities. The analysis also revealed that cleanup of the river could yield $2.3 million in additional revenue from recreation. In 1983, the former owner of the zinc mine was sued by the Colorado Attorney General for the $4.8 million cleanup costs; 5 years later, ecological recovery was considerable (Brandt 1993).

Agriculture and forestry are major industries. Agriculture includes dryland and irrigated farming and livestock grazing. Livestock are frequently moved between high-elevation summer pastures and low-elevation winter pastures.

Human population is not very dense in the Rocky Mountains, with an average of four people per square kilometer (10 per square mile) and few cities with over 50,000 people. However, the human population grew rapidly in the Rocky Mountain states between 1950 and 1990. The 40-year statewide increases in population range from 35% in Montana to about 150% in Utah and Colorado. The populations of several mountain towns and communities have doubled in the last 40 years. Jackson Hole, Wyoming, increased 260%, from 1,244 to 4,472 residents, in 40 years.


Every year the scenic areas and recreational opportunities of the Rocky Mountains draw millions of tourists. People from all over the world visit the sites to hike, camp, or engage in mountain sports. In the summer, main tourist attractions are

Missing image
Snowmelt runoff fills a reservoir in the Rocky Mountains near Dillon, Colorado.

Canadian National Parks in the mountain range are

Glacier National Park (U.S.) and Waterton Lakes National Park border each other on the U.S./Canadian border and collectively are known as the Waterton-Glacier International Peace Park. (See also International Peace Park.)

In the winter, skiing is the main attraction. The major ski resorts are:

Snowpack accumulation at 14,255 ft. on Longs Peak in Rocky Mountain National Park (photo courtesy of USDA).
Snowpack accumulation at 14,255 ft. on Longs Peak in Rocky Mountain National Park (photo courtesy of USDA).

(The adjacent Columbia Mountains in British Columbia and Idaho contain major resorts such as Schweitzer, Panorama and Kicking Horse.)

The main language is English.


The Rocky Mountains have a highland climate. The average temperature in the Rockies per year is 43 F (6 C). July is the hottest month with an average temperature of 82 F (28 C). In January, the average monthly temperature is 7 F (−14 C), making it the coldest month in the Rockies. The average precipitation per year is approximately 14 inches (360 mm).

The summers in the Rockies are warm and dry, because the western fronts impede the advancing of water-carrying storm systems. The average temperature in summer is 59 F (15 C) and the average precipitation is 5.9 inches (150 mm). Winter is usually wet and very cold, with an average temperature of 28 F (−2 C) and average snowfall of 11.4 inches (29.0 cm). In spring, the average temperature is 40 F (4 C) and the average precipitation is 4.2 inches (107 mm). And in the fall, the average precipitation is 2.6 inches (66 mm) and the average temperature is 44 F (7 C).


  • Athearn, R. G. 1960. High country empire: the High Plains and Rocky Mountains. McGraw-Hill, New York. 358 pp.
  • Brandt, E. 1993. How much is a gray wolf worth? National Wildlife 31:412.
  • Buchholtz, C. W. 1983. Rocky Mountain National Park: a history. Colorado Associated University Press, Boulder. 255 pp.
  • Grove, J. M. 1990. The little ice age. Rutledge Press, New York. 498 pp.
  • Jackson, D. 1962. Letters of the Lewis and Clark expedition with related documents 17831854. University of Illinois Press, Urbana. 728 pp.
  • Kay, C. E. 1994. Aboriginal overkill. Human Nature 5:359398.
  • Lavender, D. 1975. The Rockies. Harper and Row, New York. 433 pp.
  • Knight, D. H. 1994. Mountains and plains: the ecology of Wyoming landscapes. Yale University Press, New Haven, Conn. 338 pp.
  • Peterson, J. A., editor. 1986. Paleotectonics and sedimentation in the Rocky Mountain Region, United States. Memoir 41, American Association of Petroleum Geologists. Tulsa, Okla. 693 pp.
  • Pierce, K. L. 1979. History and dynamics of glaciation in the northern Yellowstone National Park area. Professional Paper 729-F. U.S. Geological Survey, Washington, D.C. 90 pp

External links


ca:Rocky Mountains cs:Skalnat hory da:Rocky Mountains de:Rocky Mountains fr:Montagnes Rocheuses nl:Rocky Mountains ja:ロッキー山脈 pl:Gry Skaliste pt:Montanhas Rochosas sl:Skalno gorovje fi:Kalliovuoret sv:Klippiga bergen


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