Satawal is a small flat coral island in the west central Caroline Islands about 1050 km east-south-east of Yap Island, at latitude 7'21' N, longitude 147'02' E. Although its surface is locally somewhat irregular, its greatest height is not more than about 4 meters above mean low water. Its long axis is about east-west and its area is 1.3 square km. It is surrounded by a fringing reef upward of 100 meters wide. It has no lagoon, so would be classified according to Tayama's scheme as a table reef. From the viewpoint of land ecology it is an atoll. The substratum varies from sandy to boulders, with some peat very locally. The beaches are sandy around the western half, of pebbles and cobbles around the eastern half.