The Hawaiian Islands are an archipelago of 20 islands and atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles (2,400 km) from the Island of Hawaiʻi in the south to northernmost Kure Atoll. Excluding Midway, which is an unincorporated territory of the United States, the Hawaiian Islands form the U.S. State of Hawaii. Once known as the Sandwich Islands, the archipelago takes its name from the largest island in the group.

This archipelago represents the exposed peaks of a great undersea mountain range known as the Hawaiian-Emperor seamount chain, formed by volcanic activity over a hotspot in the earth's mantle. At about 1,860 miles (3,000 km) from the nearest continent, the Hawaiian Island archipelago is the most isolated grouping of islands on Earth.