Kelso Dunes, also known as the Kelso Dune Field, is the largest field of eolian sand deposits in the Mojave Desert. The region is protected by the Mojave National Preserve and is located near the town of Baker, San Bernardino County, California, and the Preserve Visitor Center. The dune field covers 45 square miles (120 km2) and includes migrating dunes, vegetation-stabilized dunes, sand sheets, and sand ramps. The tallest dunes rise up to 650 feet (200 m) above the surrounding terrain.
The dunes are composed predominantly of light-colored quartz and feldspar, most likely eroded from the granitics of the San Bernardino Mountains to the southwest. Magnetite and amphibole can also be found, often accumulating at the dune crests.
Kelso Dunes represent part of a much larger sand transport system, which includes the nearby Devils Playground region. The composition and morphology of the sand grains indicate that most originated from the Mojave River sink near Afton Canyon, which lies to the west of the dunes' current location. The sand has accumulated at the southeastern end of the Soda Lake-Kelso basin, where the Granite Mountains and Providence Mountains form a barrier to prevailing winds. At present, only the area around the Mojave River sink and the westernmost parts of Devil's Playground are receiving new sand through this system; sand is no longer accumulating at Kelso Dunes itself.