What canyon did the Colorado River carve?
Quick answer
The Colorado River carved the Grand Canyon in northern Arizona. The canyon is about 446 km (277 mi) long, up to 29 km (18 mi) wide and about 1,857 m (6,093 ft) deep. The river began cutting it about 5–6 million years ago, exposing rock layers up to nearly 2 billion years old.
Key facts
- Location
- Arizona, USA
- Length
- About 446 km (277 mi)
- Depth
- About 1,857 m (6,093 ft)
- National park since
- 1919
How it formed
Geologists still debate the details, but the main steps are well understood.
- The Colorado Plateau was slowly pushed upward by tectonic forces.
- As the land rose, the Colorado River cut downward, carrying away sand and rock.
- Rain, frost and side streams widened the canyon; see what weathering is.
- Over millions of years, this created the deep, layered gorge seen today.
A history book in rock
| Rock layer | Approximate age |
|---|---|
| Kaibab Limestone (rim) | 270 million years |
| Redwall Limestone | 340 million years |
| Vishnu Schist (bottom) | About 1.7–1.8 billion years |
Walking from the rim to the river is like traveling back nearly 2 billion years.
Rims and visiting
| Area | Notes |
|---|---|
| South Rim | Open all year; most visited; Grand Canyon Village |
| North Rim | About 300 m higher, open mid-May to mid-October |
| Grand Canyon West | Run by the Hualapai Tribe; home to the glass Skywalk |
Rafting trips through the canyon on the Colorado River can last up to three weeks. Hikers are warned not to try to reach the river and back in one day in summer, when temperatures at the bottom can exceed 40 °C.
People of the canyon
Native American peoples, including the Havasupai, Hualapai, Navajo and Hopi, have deep ties to the canyon. The Havasupai still live in the village of Supai, deep in a side canyon, reachable only on foot, by mule or by helicopter.
Exploration
In 1869, one-armed Civil War veteran John Wesley Powell led the first known expedition by boat through the canyon. President Theodore Roosevelt protected it as a national monument in 1908, and it became a national park in 1919.
The Colorado River today
The river supplies water to about 40 million people in seven US states and Mexico. Dams such as Hoover Dam and Glen Canyon Dam control its flow, and drought has lowered its reservoirs. For America’s longest river, see the longest river in the United States.
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