Coral coasts are found throughout the Hawaiian Islands, in both the main part of the archipelago and the remote Northwestern Hawaiian Islands (NWHI). The main Hawaiian Islands feature non-structural reef communities, fringing reefs and two barrier reefs. In addition to hosting corals, fish and other reef biota, these reefs provide substrate for the island beaches when waves pulverize the calcareous reef structures.
The NWHI stretch over 2,000 km westward of the main Hawaiian Islands. This older part of the Hawaiian Archipelago consists of tiny islands, atolls, submerged banks and reefs. The reefs in this region are possibly the healthiest reef ecosystems in the United States. They host over 7,000 species, including many that are rare and endangered. On June 15, 2006, the President of the United States designated nearly 140,000 square miles of the NWHI as a national monument.