Colorado River, Marble Canyon marks the beginning of the Grand Canyon.

The Colorado River starts it's journey through Grand Canyon by slicing into the earth downstream of Lee's Ferry, at the northeastern tip of the park. While the walls gradually rise, the river cuts downward, forming the narrow, steep-walled Marble Canyon. About 80 miles downstream of Lee's Ferry is where Marble Canyon gives way to the deeper, broader Grand Canyon. Although Marble Canyon bears little resemblance to the expansive canyon downstream of it, it cuts through the same rocks and is considered part of the same geological formation.

Marble Canyon is the section of the Colorado River canyon in northern Arizona from Glen Canyon Dam to the confluence with the Little Colorado River, which marks the beginning of the Grand Canyon. Marble Canyon marks the western boundary of the Navajo Nation. In 1975, the former Marble Canyon National Monument, which followed the Colorado River northeast from the Grand Canyon to Lee's Ferry, was made part of Grand Canyon National Park.
At Marble Canyon you cross over the Colorado River via the new Navajo Bridge. There is a small visitor center nearby the old bridge where you can learn about its construction and walk out over the old bridge and look at the river and canyon below.
Marble Canyon is 44 Miles from Jacob Lake Inn and will take roughly 50 minutes to drive.