Double Arch takes its name because of it consists of two arches that share the same stone as a foundation for both of their outer legs. It is one of the more known features of Arches National Park. Double Arch was formed differently from most of the arches in Arches National Park. It is what is known as a pothole arch. It is formed by water erosion from above rather than more typical erosion from the side. The larger opening has a span of 45 m (148 feet) and a height of 32 m (104 feet).