Hawaii ( hə-WY-ee; Hawaiian: Hawaiʻi [həˈvɐjʔi, həˈwɐjʔi]) is an island state of the United States, in the Pacific Ocean about 2,000 miles (3,200 km) southwest of the U.S. mainland. One of the two non-contiguous U.S. states (along with Alaska), it is the only state not on the North American mainland, the only state that is an archipelago, and the only state in the tropics.

Hawaii consists of 137 volcanic islands that comprise almost the entire Hawaiian archipelago (the exception, which is outside the state, is Midway Atoll). Spanning 1,500 miles (2,400 km), the state is physiographically and ethnologically part of the Polynesian subregion of Oceania. Hawaii's ocean coastline is consequently the fourth-longest in the U.S., at about 750 miles (1,210 km). The eight main islands, from northwest to southeast, are Niʻihau, Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Kahoʻolawe, Maui, and Hawaiʻi, after which the state is named; the last is often called the "Big Island" or "Hawaii Island" to avoid confusion with the state or archipelago. The uninhabited Northwestern Hawaiian Islands make up most of the Papahānaumokuākea Marine National Monument, the largest protected area in the U.S. and the fourth-largest in the world.

Of the 50 U.S. states, Hawaii is the fourth-smallest in land area and the 11th-least populous; but with 1.4 million residents, it ranks 13th in population density. Two-thirds of Hawaii residents live on O'ahu, home to the state's capital and largest city, Honolulu. Hawaii is one of the most demographically diverse U.S. states, owing to its central location in the Pacific and over two centuries of migration.