Grand Canyon slices roughly east–west through the southwestern edge of the Colorado Plateau, an uplifted platform with an average elevation of 6,000 feet centering on the Southwest’s Four Corners area and covering about 130,000 square miles.

The colorful sedimentary rock layers of the Colorado Plateau, broken by faults and carved by streams, are revealed in cliffs and canyons. Ninety percent of the semi-arid plateau is drained by the Colorado River and its tributaries.

Within the major physiographic province of the Colorado Plateau, shifts along fault lines have created several distinct, smaller plateaus. The canyon’s north side is dominated by the Kaibab and Kanab Plateaus. On the south is the Coconino Plateau. The eastern section of Grand Canyon, known as Marble Canyon, runs roughly north–south through the lower elevations of the Marble Platform.

From the heights of the Kaibab Plateau (9,200 feet) to the Marble Canyon Airport (3,603 feet), the Grand Canyon region encompasses a number of environments. Inside the boundaries of Grand Canyon National Park (1.2 million acres), the North Rim’s Grand Canyon Lodge sits 1,180 feet higher than Grand Canyon Village on the South Rim, with 10 air miles (220 road miles) between.

Grand Canyon ends at the Grand Wash Cliffs, which form the edge of present-day Lake Mead, impounded by Hoover Dam. Here begins another major physiographic province, the alternating valleys and escarpments of the Great Basin.

The Colorado River, the canyon’s main artery, flows from north-central Colorado to the Gulf of Mexico. Glen Canyon Dam impounds the river northeast of Grand Canyon, restricting flows and changing the river’s muddy, red-brown water to cold, clear green. The distance from rim to river varies but averages 4,000 feet. The river averages about 35 feet deep and varies in width from 76 feet to more than 300 feet.

The 277-mile stretch from Lees Ferry to the Grand Wash Cliffs drops 1,900 feet in elevation and crosses countless tributary canyons. Debris from these side canyons creates the most common type of rapid, a constriction rapid, where water tumbles over boulders swept into the main channel by floods. River runners encounter more than 160 rapids on the journey through the canyon, and the Colorado River drops in gradient about eight feet per mile.

Most of Grand Canyon’s tributaries flow only intermittently after rainstorms or during spring melt. About a dozen have year-round water, including the Little Colorado River, Bright Angel Creek, and Havasu Creek.

The Colorado River and Grand Canyon create a barrier between Arizona’s northwest corner and the rest of the state. Until the Navajo Bridge was completed in 1929, the Arizona Strip was relatively isolated. Even today, the corner of Grand Canyon known as Tuweep or Toroweap requires a long drive through ranch country and Bureau of Land Management (BLM) land.