The Grand Canyon is not the biggest canyon on Earth by any single standard measurement. It is not the deepest, the longest, the widest, or the largest by volume. Several gorges in the Himalayas and the Andes plunge deeper, a submarine canyon in the Bering Sea dwarfs it in volume by orders of magnitude, and a canyon buried beneath Greenland’s ice sheet stretches nearly twice its length. What makes the Grand Canyon extraordinary is its combination of depth, width, length, and spectacularly exposed rock layers, all in a landscape accessible enough for millions of people to stand at its rim and look down. But “biggest” depends entirely on what you measure, and the Grand Canyon loses most of those contests.
What Makes the Grand Canyon Stand Out
The Grand Canyon stretches roughly 446 kilometers (277 miles) through northern Arizona, reaches widths of up to 29 kilometers (18 miles), and drops as deep as about 1,800 meters (just over a mile) from rim to river. Those are genuinely impressive numbers, but the canyon’s real claim to fame is the package deal. Few other canyons combine that depth and width while also exposing nearly two billion years of Earth’s geological history in neatly layered, colorful rock strata. The arid climate and relatively open landscape make the whole thing visible in a way that deeper gorges in the Himalayas, buried under vegetation or squeezed between towering peaks, simply are not.
Geologically, the canyon’s story is more complicated than it might seem. Evidence from rock and mineral analysis suggests that significant uplift of the region began during the late Cretaceous period, tens of millions of years ago, setting the stage for the Colorado River to eventually carve the canyon into the rising plateau.1American Journal of Science. Late Cretaceous Uplift of Grand Canyon: Evidence From Fluid Inclusions The exact timeline of the canyon’s carving has been debated for over a century, with some researchers arguing for a relatively young canyon (five to six million years old) and others pointing to evidence that parts of it are far older. Either way, the canyon we see today is the product of river erosion cutting through rock that was being pushed upward by tectonic forces, a process that gave the Colorado Plateau its dramatic elevation and exposed those famous layers.
Deeper Gorges on Land
If depth is the measure, several canyons surpass the Grand Canyon by a wide margin. The most commonly cited rivals are in the Himalayas and the Andes.
The Kali Gandaki valley in Nepal, which slices between the Annapurna and Dhaulagiri massifs, is frequently called the deepest gorge in the world.2ScienceDirect. Glaciers and mass wasting processes: their influence on the shaping of the Kali Gandaki valley (higher Himalaya of Nepal) The depth measurement depends on how you define it. If you measure from the river at the valley floor to the summits of the flanking peaks, the drop is well over 5,000 meters, roughly three times the depth of the Grand Canyon. Some geographers object to this measurement because the peaks are set back from the gorge’s rim, and using the nearest ridgeline gives a smaller (though still enormous) number. But either way, the Kali Gandaki is in a different league for sheer vertical relief.
Nearby, the Yarlung Tsangpo Gorge in Tibet is another contender, carved by the river that becomes the Brahmaputra as it bends sharply around the eastern Himalayan syntaxis. The Himalayas are dissected by some of the deepest and most impressive gorges on Earth, and the Tsangpo is arguably the most dramatic of them all.3PubMed. Tectonic control of Yarlung Tsangpo Gorge revealed by a buried canyon in Southern Tibet Depending on measurement method, its depth rivals or exceeds the Kali Gandaki’s. Both gorges owe their extreme depth to a geological arms race: the rivers were already flowing when the Himalayas began rising, and the water cut downward roughly as fast as the mountains rose, a process geologists call antecedent drainage.
In South America, the Andes host their own set of extreme canyons. The deepest valleys in the Andes have been cut in southern Peru by the Ríos Cotahuasi, Ocoña, and Colca, all in a narrow band around 15 to 16 degrees south latitude.4ScienceDirect. Geochronologic and stratigraphic constraints on canyon incision and Miocene uplift of the Central Andes in Peru The Cotahuasi Canyon and neighboring Colca Canyon both exceed 3,000 meters in depth from rim to river, making them roughly twice as deep as the Grand Canyon. These canyons are less famous internationally partly because they are more remote and partly because, unlike the Grand Canyon, they do not sit in a flat plateau that makes their full depth immediately visible to a visitor standing at the edge.
Why “Biggest” Is Hard to Pin Down
Part of the reason the Grand Canyon’s reputation persists despite all these deeper rivals is that “biggest” is not a precise geological term. You can rank canyons by depth (vertical distance from rim to floor), by length, by width, by total volume of rock removed, or by some combination of these. The Grand Canyon is not the champion in any single category, but it scores respectably in all of them, which is unusual. Most of the deeper gorges are relatively narrow. Most of the longer canyons are shallow over much of their length. The Grand Canyon’s broad, open profile and extended length give it an impressive total volume even though individual canyons beat it on every individual axis.
There is also the question of what counts as a canyon versus a valley. The Kali Gandaki, for instance, is sometimes classified as a gorge or a valley rather than a canyon, partly because its walls are not always the steep, near-vertical cliffs that the word “canyon” conjures. These distinctions are mostly semantic, not scientific, but they matter when someone asks whether the Grand Canyon is “the biggest canyon” because the answer can change depending on which landforms you include in the comparison.
Submarine Canyons Dwarf Everything on Land
If you extend the comparison below sea level, terrestrial canyons start to look modest. The ocean floor is scored by enormous submarine canyons, carved not by rivers and rain but by underwater sediment flows called turbidity currents, along with slumping and erosion from ocean currents. The largest of these sit along the Bering Sea margin off Alaska.
Zhemchug Canyon, cut into the continental shelf of the Bering Sea, is often cited as the world’s largest submarine canyon. Early surveys estimated its volume at roughly 8,500 cubic kilometers, far exceeding most other submarine canyons, which typically have volumes under 500 cubic kilometers.5Marine Geology. The structure and origin of the large submarine canyons of the Bering Sea Later detailed work found that three of the Bering Sea’s seven large canyons, including Zhemchug, Bering, and Navarinsky, are an order of magnitude larger than any submarine canyons along the continental U.S. coastline. Bering Canyon alone is about 400 kilometers long, and both Navarinsky and Zhemchug are each roughly 100 kilometers wide where they meet the shelf break.6GSA Bulletin. Development of large submarine canyons in the Bering Sea, indicated by morphologic, seismic, and sedimentologic characteristics By volume, Zhemchug Canyon alone may contain more empty space than the Grand Canyon many times over.
Submarine canyons do not look or behave like their land-based counterparts. Research on the Congo Canyon, one of the most active submarine canyons in the world, has shown that the erosion patterns inside submarine canyons differ significantly from those in meandering rivers. In a river, most erosion happens on the outer bend of curves. In the Congo Canyon, outer-bend erosion accounted for only about 10 percent of the total, with powerful turbidity currents scouring the canyon floor in patterns that have no close analog on land.7Geomorphology. Time-lapse surveys reveal patterns and processes of erosion by exceptionally powerful turbidity currents that flush submarine canyons: A case study of the Congo Canyon These flows can move at highway speeds and carry enormous volumes of sediment, flushing submarine canyons in events that last hours or days rather than the millions of years required for river-carved canyons on land.
Canyons Hidden Beneath Ice Sheets
Some of the most dramatic canyon discoveries in recent decades have come from places where no human eye has ever seen the canyon walls. Ice-penetrating radar surveys over Greenland revealed a subglacial mega-canyon stretching roughly 750 kilometers beneath the island’s central ice sheet.8PubMed. Paleofluvial mega-canyon beneath the central Greenland ice sheet That length alone would make it nearly twice as long as the Grand Canyon. The researchers who discovered it believe the canyon predates the ice sheet itself, meaning it was carved by rivers before Greenland’s glaciation and has been preserved beneath kilometers of ice ever since. Its presence has influenced how water flows at the base of the ice sheet over millions of years of glacial cycles.
An even more extreme feature sits beneath East Antarctica. Radar-derived maps of the bedrock under Denman Glacier revealed a trough plunging about 3.5 kilometers below sea level, making it the deepest known canyon on Earth’s surface, nearly half the height of Mount Everest measured downward rather than upward.9Nature Geoscience. Antarctic video reveals deepest canyon on Earth Whether this feature qualifies as a “canyon” in the traditional sense is debatable. It may be partly tectonic in origin, shaped by rifting and crustal thinning as much as by glacial erosion. But in terms of raw depth below the surrounding surface, nothing else on Earth comes close.
These sub-ice discoveries highlight how incomplete our picture of Earth’s topography still is. Until radar technology made it possible to peer through ice sheets kilometers thick, these enormous features were invisible. It is entirely possible that additional mega-canyons remain hidden beneath Antarctica, where the bedrock has been mapped at much lower resolution than Greenland.
How Different Canyon Types Form
The reason so many different landforms can be called “canyons” is that very different processes can produce similar-looking results. The Grand Canyon was carved primarily by river erosion: the Colorado River cut downward through sedimentary rock as the Colorado Plateau rose. In this type of canyon, the river’s ability to deepen the channel depends on factors like water volume, sediment load, and the hardness of the rock. In bedrock-bound canyons like the Grand Canyon, depth is the main dimension that adjusts as water flow increases, unlike rivers in softer sediment where the channel tends to widen instead.10Earth Surface Processes and Landforms. Covariation in width and depth in bedrock rivers That is part of why the Grand Canyon is so deep relative to many other river valleys: the hard rock forced the Colorado to cut down rather than spread out.
In softer sediment systems, rivers behave differently. As total sediment load increases, a river can only transport more material by widening, because the intensity of sediment flow per unit of channel width tends to plateau.11PubMed Central. Sediment load determines the shape of rivers This helps explain why many river valleys in low-lying sedimentary basins are broad and shallow rather than narrow and deep. The Grand Canyon’s hard limestone and sandstone layers resisted widening and instead channeled the river’s energy downward, producing the steep-walled profile the canyon is known for.
Himalayan gorges, by contrast, owe their extreme depth partly to the same river-versus-rock dynamic but amplified by active tectonic uplift. When mountains rise faster than a river can erode, the river eventually loses the race and gets diverted. But when the river keeps pace with the uplift, the result is an antecedent gorge: a canyon that grows deeper as the mountains grow taller, with the river maintaining its original course like a saw blade cutting through a board being pushed upward. Both the Kali Gandaki and the Yarlung Tsangpo are products of this process, which is why they cut through some of the highest mountains on Earth rather than going around them.
Submarine canyons form through yet another set of mechanisms. Some began as river valleys during ice ages when sea levels were lower, then were maintained and deepened by turbidity currents after the sea rose again. Others formed entirely underwater through slope failure and sediment flows. The sheer scale of submarine canyons in the Bering Sea reflects the massive volumes of sediment delivered to the continental margin during glacial periods, when rivers draining ice sheets carried enormous loads of debris to the shelf edge.
Canyons Beyond Earth
If you remove the restriction to our own planet, the Grand Canyon becomes an even smaller player. Valles Marineris on Mars is the largest known canyon in the solar system, stretching roughly 4,000 kilometers long, up to 200 kilometers wide, and as much as 7 kilometers deep. It would span the entire continental United States from coast to coast. Despite its enormous size, the mechanism responsible for forming Valles Marineris remains debated. One model proposes that the troughs formed through a combination of tectonic rifting and crustal subsidence: blocks of Martian crust lost support and sank, with sediment loading inside the troughs and viscous deformation at the base of the crust amplifying the subsidence to a predicted depth of roughly 8.6 kilometers, which matches the observed depths reasonably well.12Journal of Geophysical Research: Planets. The formation of Valles Marineris: 3. Trough formation through super‐isostasy, stress, sedimentation, and subsidence
What makes Valles Marineris fundamentally different from the Grand Canyon is that it was probably not carved by flowing water, at least not primarily. While there is evidence of water having flowed through parts of it at some point in Martian history, the canyon’s formation appears to be more structural, driven by the planet’s crust pulling apart and collapsing. The Grand Canyon is the product of a river patiently grinding through stone. Valles Marineris is the product of a planet’s surface splitting open. The two features look superficially similar in cross-section but arose from completely different processes, which is a useful reminder that canyon-like shapes can be produced in many ways across the solar system.
Other bodies in the solar system host their own dramatic surface features. Jupiter’s moon Europa has long fractures in its ice shell, Saturn’s moon Titan has valleys that may have been carved by flowing liquid hydrocarbons, and Pluto’s surface revealed cliff faces and troughs when the New Horizons spacecraft flew past in 2015. None of these are “canyons” in the strict terrestrial sense, but they underscore the same point: wherever there is a surface and a force acting on it, whether that force is water, ice, tectonics, or exotic chemistry, deep incisions tend to follow. Earth’s canyons, including the Grand Canyon, are just one local expression of a universal process of surfaces being cut, collapsed, or dissolved over time.