The park is divided into four districts: the Island in the Sky, the Needles, the Maze, and the combined rivers—the Green and Colorado—which carved two large canyons into the Colorado Plateau. It preserves a colorful landscape eroded into countless canyons, mesas, and buttes by the Colorado River, the Green River, and their respective tributaries.
Mammals that roam this park include;
At least 273 species of birds inhabit the park. A variety of hawks and eagles are found, including the Cooper’s hawk, the northern goshawk, the sharp-shinned hawk, the red-tailed hawk, the golden and bald eagles, the rough-legged hawk, the Swainson’s hawk, and the northern harrier.
Several species of owls are found, including the great horned owl, the northern saw-whet owl, the western screech owl, and the Mexican spotted owl. Grebes, woodpeckers, ravens, herons, flycatchers, crows, bluebirds, wrens, warblers, blackbirds, orioles, goldfinches, swallows, sparrows, ducks, quail, grouse, pheasants, hummingbirds, falcons, gulls, and ospreys are some of the other birds that can be found.
Several reptiles can be found, including eleven species of lizards and eight species of snake (including one rattlesnake). The common king snake and prairie rattlesnake have been reported in the park, but not confirmed by the National Park Service.
Official data documents the desert climate with less than 250 mm of annual rainfall, as well as very warm, mostly dry summers and cold, occasionally wet winters. Snowfall is generally light during the winter.