Comb Wash is a valley in southeastern Utah, in San Juan County. It runs from Elk Ridge in the north approximately 35 miles (56 km) to the south, where it merges with the San Juan River at an elevation of about 4200 feet (1280 m). The eastern edge of the wash forms steep cliffs of Navajo Sandstone, rising in places to 1000 feet (300 m) above the valley floor.
On the western edge of Comb Wash is a series of canyons draining Cedar Mesa. To the north is Arch Canyon, which has Texas Canyon as an upper tributary. In the central section are Mule Canyon, Dry Wash, and the combined outlet of Fish and Owl Canyons. To the south are McCloyd's Canyon (containing the Moon House ruin) and Road Canyon. Scattered throughout these canyons are cliff dwellings of the Ancestral Puebloans.
State Route 95 crosses the northern part of Comb Wash, while U.S. Route 163 crosses further south. Running along the wash is a primitive road, often impassable after floods. Nearby are the Natural Bridges National Monument, the Grand Gulch Primitive Area, the Valley of the Gods scenic area, and Goosenecks State Park.