This island lies in a small separate atoll along with Goidhu and Fehendhu, as well as four smaller uninhabited islets. Goidhoo Atoll (also Goidu or Goifulhafehendhu), Horsburgh Atoll in the Admiralty Chart, is separated from South Maalhosmadulhu by a 6 nmi (11 km) broad channel. This atoll is oval in shape and small, its greatest length being 16 km (10 mi). The total area of the atoll (including lagoon and reef flat) is 105 km2 (26,000 acres), of which only 1.7 km2 (420 acres) is dry land. The inner lagoon has a depth of 17 to 20 fathoms (31 to 37 m); it has a sandy bottom mixed with mud and clay. Unlike the lagoons of most small atolls of the Maldives, this lagoon is free from coral heads in its centre.