The “moon” of Moon Hill was once a cave that eroded over time to form a wide, semi-circular hole close to the summit. This hole, or arch, is 50 metres (about 160 ft.) high and approximately 50 metres wide.

Moon Hill is located to the south of Yangshuo across the Jingbao river along China National Highway 321. It has an elevation of 380 m (1,250 ft), while the hill is 230 m (750 ft) in relative height and 410 m (1,350 ft) in length. The arch is about 50 meters in height.

The region of space around an object where a satellite could orbit indefinitely is called the Hill sphere, roughly defined as where the object's gravitational field is stronger than that exerted by another object outside the sphere.