The Rocky Mountains stretch 3,000 miles (4,800 kilometers)[3] in straight-line distance from the northernmost part of Western Canada, to New Mexico in the Southwestern United States.

Being the easternmost portion of the North American Cordillera, the Rockies are distinct from the tectonically younger Cascade Range and Sierra Nevada, which both lie farther to its west.

[citation needed] The angle of subduction was shallow, resulting in a broad belt of mountains running down western North America.

The western edge of the Rockies includes ranges such as the Wasatch near Salt Lake City, the San Juan Mountains of New Mexico and Colorado, the Bitterroots along the Idaho-Montana border, and the Sawtooths in central Idaho.

Triple Divide Peak (2,440 m or 8,020 ft) in Glacier National Park is so named because water falling on the mountain reaches not only the Atlantic and Pacific but Hudson Bay as well.

During the Paleozoic, western North America lay underneath a shallow sea, which deposited many kilometers of limestone and dolomite.

[7]: 76 In the southern Rockies, near present-day Colorado, these ancestral rocks were disturbed by mountain building approximately 300 Ma, during the Pennsylvanian.

They consisted largely of Precambrian metamorphic rock forced upward through layers of the limestone laid down in the shallow sea.

Terranes began colliding with the western edge of North America in the Mississippian (approximately 350 million years ago), causing the Antler orogeny.

This low angle moved the focus of melting and mountain building much farther inland than the normal 300 to 500 kilometres (200 to 300 mi).

Scientists hypothesize that the shallow angle of the subducting plate increased the friction and other interactions with the thick continental mass above it.

Tremendous thrusts piled sheets of crust on top of each other, building the broad, high Rocky Mountain range.

These ice ages left their mark on the Rockies, forming extensive glacial landforms, such as U-shaped valleys and cirques.

Examples of some species that have declined include western toads, greenback cutthroat trout, white sturgeon, white-tailed ptarmigan, trumpeter swan, and bighorn sheep.

[9] Since the last great ice age, the Rocky Mountains were home first to indigenous peoples including the Apache, Arapaho, Bannock, Blackfoot, Cheyenne, Coeur d'Alene, Kalispel, Crow Nation, Flathead, Shoshone, Sioux, Ute, Kutenai (Ktunaxa in Canada), Sekani, Dunne-za, and others.

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 with the crest of the Continental Divide, rock walls that Native Americans built for driving game date back 5,400–5,800 years.

A growing body of scientific evidence indicates that indigenous people had significant effects on mammal populations by hunting and on vegetation patterns through deliberate burning.

The Spanish explorer Francisco Vázquez de Coronado—with a group of soldiers and missionaries marched into the Rocky Mountain region from the south in 1540.

[21] In 1610, the Spanish founded the city of Santa Fe, the oldest continuous seat of government in the United States, at the foot of the Rockies in present-day New Mexico.

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.

[24] He arrived at Bella Coola, British Columbia, where he first reached saltwater at South Bentinck Arm, an inlet of the Pacific Ocean.

On July 24, 1832, Benjamin Bonneville led the first wagon train across the Rocky Mountains by using South Pass in the present State of Wyoming.

In 1841, James Sinclair, Chief Factor of the Hudson's Bay Company, guided some 200 settlers from the Red River Colony west to bolster settlement around Fort Vancouver in an attempt to retain the Columbia District for Britain.

Glacier National Park (MT) was established with a similar relationship to tourism promotions by the Great Northern Railway.

In 1905, U.S. President Theodore Roosevelt extended the Medicine Bow Forest Reserve to include the area now managed as Rocky Mountain National Park.

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.

An economic analysis of mining effects at this site revealed declining property values, degraded water quality, and the loss of recreational opportunities.

In 1983, the former owner of the zinc mine was sued by the Colorado Attorney General for the $4.8 million cleanup costs; five years later, ecological recovery was considerable.