Arches National Park is in eastern Utah adjacent to the Colorado River, north of Moab, Utah. It contains more than 2,000 natural sandstone arches, including the well-known Delicate Arch, which constitute the highest density of natural arches in the world. The national park lies above an underground evaporite layer or salt bed, which is the main cause of the formation of the arches, spires, balanced rocks, sandstone fins, and eroded monoliths in the area. The park consists 119.81 sq miles. Wikipeda