Island
An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island in a river or a lake island may be called an eyot or ait, and a small island off the coast may be called a holm. A grouping of geographically or geologically related islands is called an archipelago, such as the Philippines.
Territories of the United States
The territories do not have counties as administrative divisions. The U.S. Census Bureau counts the following as county-equivalents: the 78 municipalities of Puerto Rico, the 3 main islands of the U.S. Virgin Islands, all of Guam, the 4 municipalities of the Northern Mariana Islands, and the 3 districts and 2 atolls of American Samoa. The U.S. Census Bureau also counts each of the islands in the U.S. Minor Outlying Islands as county-equivalents.