Canyonlands National Park, Utah. Standing on an overhanging slab of Cedar Mesa Sandstone in the Maze District of Canyonlands National Park, a hiker is dwarfed by the canyon carved by the Colorado River. Major John Wesley Powell floated beneath these cliffs during his multiple explorations of the Colorado River’s canyons during the late 1800s. The Needles District of Canyonlands lies just across the canyon to the east while the Island-in-the-Sky District lies just upstream north of the confluence with the Green River.