What is the largest canyon in the United States?

The Grand Canyon is the largest canyon in the United States and one of Earth’s most dramatic examples of river erosion. Carved primarily by the Colorado River, it cuts across northern Arizona for roughly 446 kilometers. In places it reaches more than 1.6 kilometers in depth, exposing layers of rock that record nearly two billion years of geological history.

The canyon’s immense scale developed through uplift of the Colorado Plateau and the continued downcutting of the Colorado River, aided by tributary streams, weathering, and ice. Its layered walls display rocks from different geological eras, making the canyon an important natural laboratory as well as a landmark. The river itself still flows through the canyon, although dams and water management influence its modern environment.

Grand Canyon National Park protects much of the most famous section and was established in 1919. The canyon is often confused with nearby Antelope Canyon, Bryce Canyon, or Canyonlands, but those are distinct landscapes. “Largest” is a broad trivia description rather than a strict measurement category; by overall size and fame, the Grand Canyon is the standard answer.