South Canyon is a rugged, mostly trail-less route into Marble Canyon, the narrow northern reach of the Grand Canyon where the walls close to barely a mile apart above the Colorado River. It is a route for experienced canyoneers and desert backpackers rather than a maintained trail, usually done as a three-to-four-day trip, dropping from the high, flat Marble Platform down through the rock to the river.

The descent follows the bed and benches of South Canyon down to the Colorado near River Mile 31.5, an area rich in history and natural wonder. Here the river passes Vasey's Paradise, a startling spring that bursts straight out of the Redwall cliff in a curtain of greenery and falling water, and Stanton's Cave, a large cavern that has yielded remarkable archaeological finds, including ancient split-twig animal figurines left by prehistoric people (the cave is gated to protect it and its bats). Redwall Cavern, one of the river's great sandy grottoes, lies just downstream.

Access is by rough dirt roads off House Rock Valley on the canyon's remote east side; the route is passable even in winter, though the approach roads can become briefly impassable after snow or rain. There is little reliable water until the river, the terrain demands solid route-finding and scrambling, and overnight travel requires a backcountry permit. For hikers with the skills and experience, South Canyon offers a rare, intimate way into the wild beauty of Marble Canyon.