How big is the Grand Canyon?

About 446 kilometres long following the river, up to about 29 kilometres wide and roughly 1.8 kilometres, or about a mile, deep.

How old is the Grand Canyon?

The rocks are up to about 1.8 billion years old, but the canyon itself is much younger. Many geologists date the modern canyon to roughly five to six million years ago, though some sections may follow older canyons.

What is the difference between the South Rim and North Rim?

The South Rim is lower, open all year and easier to reach. The North Rim is higher, cooler and snowier, with forests of spruce, fir and aspen, and its facilities usually close in winter.

Can you hike to the bottom of the Grand Canyon in a day?

The National Park Service strongly advises against hiking to the river and back in one day, especially in summer. The climb out takes far longer than the descent and the inner canyon can be extremely hot.

Can I explore the Grand Canyon in the app?

Yes. You can stand on a rim modelled on the Grand Canyon and explore its layered cliffs, buttes and side canyons in interactive 3D.

A mile-deep gorge that lays open nearly two billion years of Earth's history

Grand Canyon

3D landscape · South Rim, Arizona, USA

Land here and explore →

The Grand Canyon winds across northern Arizona in the south-western United States, cut into the high Colorado Plateau by the Colorado River. The US National Park Service gives its length as 277 river miles, about 446 kilometres, with a width of up to about 29 kilometres and a depth of around 1.8 kilometres, or roughly a mile. In this app you can stand on a rim modelled on the Grand Canyon and look down across its banded cliffs, buttes and side canyons in interactive 3D.

What makes the canyon so remarkable is not only its scale but what it reveals. Its walls are a cross-section through layer upon layer of rock, from limestones laid down in ancient seas to the dark, twisted schist at the bottom, formed roughly 1.7 to 1.8 billion years ago. The canyon is also a place of great cultural importance to many Native American peoples, a refuge for rare wildlife such as the California condor, and one of the most visited national parks in the United States.

Key facts

Location: Arizona, USAOn the Colorado Plateau, protected as Grand Canyon National Park
Length: About 446 km277 river miles, as measured along the Colorado River
Width: Up to about 29 kmRim to rim; about 16 km at Grand Canyon Village
Depth: About 1.8 kmRoughly a mile from the rim to the river
Oldest rocks: About 1.8 billion yearsVishnu Basement Rocks at the bottom of the inner gorge
Youngest rim rock: Kaibab LimestoneAround 270 million years old
Modern canyon: Roughly 5–6 million yearsA widely held estimate; some scientists argue parts are much older
National park: 1919Designated by the US Congress on 26 February 1919
World Heritage: 1979Inscribed by UNESCO as a natural site

Reading the rock layers

The canyon walls are a stack of sedimentary rock layers resting on much older crystalline rock. Near the top is the pale Kaibab Limestone, around 270 million years old, formed in a shallow sea, then the Toroweap Formation and the cream-coloured Coconino Sandstone, about 275 million years old, made of wind-blown sand dunes whose sloping layers and fossil footprints can still be seen. Below lie the red slopes of the Hermit Formation and the red sandstones and shales of the Supai Group, laid down roughly 285 to 315 million years ago on coastal plains and in shallow seas.

Further down, the massive Redwall Limestone, about 340 million years old, forms a sheer cliff a few hundred metres high; it is grey limestone stained red by iron-rich material washing down from above. Beneath it come the Muav Limestone, the greenish Bright Angel Shale and the brown Tapeats Sandstone, which together record a sea spreading over the land more than 500 million years ago, during the Cambrian period. Ages for these layers are refined as dating methods improve, so published figures differ slightly.

The Great Unconformity

In many places the Tapeats Sandstone sits directly on the Vishnu Schist, which is well over a billion years older. The rocks that once lay between were eroded away, leaving a gap in the record known as the Great Unconformity. In parts of the canyon, tilted layers of the Grand Canyon Supergroup partly fill this gap.

The ancient basement

At the bottom of the canyon, in the steep inner gorge, the river cuts through the Vishnu Basement Rocks. These include the dark Vishnu Schist and pink veins and bodies of granite. The schist began as sediments and volcanic rocks, which were buried deep, squeezed and heated as island arcs collided with the edge of the young North American continent roughly 1.7 to 1.8 billion years ago, turning them into metamorphic rock.

Standing beside the river, a visitor can touch rock that formed when life on Earth was still almost entirely microscopic. Looking up from there, the layers above represent hundreds of millions of years of seas advancing and retreating, deserts spreading and rivers depositing sediment, all later lifted thousands of metres above sea level as the Colorado Plateau rose.

How the Colorado River carved it

The canyon was carved mainly by the Colorado River and its tributaries, cutting down as the Colorado Plateau was slowly uplifted. Sand, gravel and boulders carried by the river, especially during floods, act like sandpaper on the riverbed. Meanwhile rain, frost, flash floods and rockfalls widen the canyon, eating back the walls. Hard layers such as the Redwall and Coconino form cliffs, while softer shales erode into gentler slopes, producing the canyon's stepped profile.

When the canyon formed is still debated. Many geologists think the modern Grand Canyon, with the Colorado River flowing through it to the Gulf of California, came together roughly five to six million years ago, when the river became integrated and began cutting rapidly. Others argue that some sections follow much older canyons, perhaps tens of millions of years old, that were later joined up. Many researchers now favour a combination: parts of the canyon are old, but the canyon as a whole is young.

The rims and the canyon's life zones

The South Rim, at roughly 2,100 metres above sea level, is open all year and is where most visitors go. The North Rim stands higher, at roughly 2,400 metres, and is cooler and wetter, with heavy winter snow; its visitor facilities and access road usually close for the winter season. Although the rims are only about 16 kilometres apart in a straight line at Grand Canyon Village, driving from one to the other takes several hours.

The change in height from river to rim creates a striking series of habitats. At the bottom, the climate is desert, with cacti, agave, mesquite and lizards, and summer temperatures that can be dangerously hot. Higher up come pinyon pine and juniper woodland, then ponderosa pine forest on the rims, and on the higher North Rim, forests of spruce, fir and aspen. In 1889 the naturalist C. Hart Merriam used the area around the San Francisco Peaks and the Grand Canyon to develop his influential idea of life zones that change with elevation.

Two squirrels, one canyon

The tassel-eared Kaibab squirrel lives only on the North Rim plateau, while its close relative, Abert's squirrel, lives on the South Rim. The canyon has kept the two populations apart long enough for them to look noticeably different.

Condors and the canyon's peoples

The California condor, with a wingspan approaching three metres, is North America's largest land bird. By 1987 so few remained that the last wild condors were taken into captivity for breeding. Captive-bred birds were released in northern Arizona from 1996, and condors can now often be seen soaring above the canyon. Lead poisoning, mainly from eating carcasses containing lead ammunition fragments, remains the biggest threat to their recovery.

People have lived in and around the canyon for thousands of years. The National Park Service recognises a number of tribes with traditional ties to the canyon, including the Havasupai, whose village of Supai lies deep in a side canyon; the Hualapai, whose lands stretch along the south side of the western canyon; the Navajo and Hopi, for whom the canyon has deep spiritual significance; and several Paiute bands, the Zuni and others. The area was protected as a national monument in 1908, became a national park in 1919 and was inscribed as a UNESCO World Heritage Site in 1979.

Visiting safely

The biggest danger at the Grand Canyon is heat. Temperatures rise as you descend, and in summer the inner canyon can be far hotter than the rim, with shade temperatures that can exceed 40°C. The National Park Service warns visitors not to try hiking from the rim to the river and back in a single day, especially in summer, and to avoid hiking in the hottest part of the day, carry plenty of water, eat salty snacks and rest in shade.

Hiking in the canyon works the opposite way to climbing a mountain: the easy part comes first. Walking down feels gentle, but the climb back out is long, steep and exhausting at altitude, and typically takes around twice as long as the descent. Park rangers often say that going down is optional, but coming up is mandatory. Staying well back from the rim edge, checking current conditions and road openings, and planning turn-around times are all essential.

Surprising facts about Grand Canyon

Rocks at the bottom of the Grand Canyon are roughly 1.8 billion years old, while those on the rim are around 270 million years old.
In places, more than a billion years of rock record is missing at the Great Unconformity.
The Coconino Sandstone near the rim is made of ancient desert sand dunes and preserves fossil footprints.
Two different kinds of squirrel live on the North and South Rims, kept apart by the canyon.
The California condor was extinct in the wild in 1987 but now flies over the Grand Canyon again.
It is often hotter at the bottom of the canyon than on the rim, so hikers walk down into the heat.

Frequently asked questions

How big is the Grand Canyon?: About 446 kilometres long following the river, up to about 29 kilometres wide and roughly 1.8 kilometres, or about a mile, deep.
How old is the Grand Canyon?: The rocks are up to about 1.8 billion years old, but the canyon itself is much younger. Many geologists date the modern canyon to roughly five to six million years ago, though some sections may follow older canyons.
What is the difference between the South Rim and North Rim?: The South Rim is lower, open all year and easier to reach. The North Rim is higher, cooler and snowier, with forests of spruce, fir and aspen, and its facilities usually close in winter.
Can you hike to the bottom of the Grand Canyon in a day?: The National Park Service strongly advises against hiking to the river and back in one day, especially in summer. The climb out takes far longer than the descent and the inner canyon can be extremely hot.
Can I explore the Grand Canyon in the app?: Yes. You can stand on a rim modelled on the Grand Canyon and explore its layered cliffs, buttes and side canyons in interactive 3D.

Keep exploring

The landscapes in Ember’s Universe are procedural 3D scenes modelled on real places. The landforms, plants and light follow the real thing, but the details are generated, not mapped.

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