Glen Canyon is a natural canyon carved by a 169.6-mile length of the Colorado River, mostly in southeastern and south-central Utah. Glen Canyon starts at the confluence of the Colorado River and the Dirty Devil River. A small part of the lower end of Glen Canyon extends into northern Arizona and terminates at Lee's Ferry, near the Vermilion Cliffs. Like the Grand Canyon farther downstream, Glen Canyon is part of the immense system of canyons carved by the Colorado River and its tributaries.

In 1963, a reservoir, Lake Powell, was created by the construction of the Glen Canyon Dam, in the Arizona portion of Glen Canyon near the brand new town of Page, inundating much of Glen Canyon under water hundreds of feet in depth.

The Glen Canyon Dam remains a central issue for modern environmentalist movements. Beginning in the late 1990s, the Sierra Club and other organizations renewed the call to dismantle the dam and drain Lake Powell in Lower Glen Canyon. Today, Glen Canyon and Lake Powell are managed by the U.S. Department of the Interior within Glen Canyon National Recreation Area.