The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and seamounts in the North Pacific Ocean, extending some 1,500 miles (2,400 kilometers) from the island of Hawai?i in the south to northernmost Kure Atoll. Formerly the group was known to Europeans and Americans as the Sandwich Islands, a name chosen by James Cook in honor of the then First Lord of the Admiralty John Montagu, 4th Earl of Sandwich. The contemporary name is derived from the name of the largest island, Hawaii Island.
Although Hawaii is now a U.S. state, it is only a part of the U.S. politically and not geographically connected or a part of North America. The state of Hawaii occupies the archipelago almost in its entirety (including the uninhabited Northwestern Hawaiian Islands), with the sole exception of Midway Island, which instead separately belongs to the United States as one of its unincorporated territories within the United States Minor Outlying Islands.
The Hawaiian Islands are 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. The islands are about 1,860 miles (3,000 km) from the nearest continent.
Captain James Cook visited the islands on January 18, 1778, and named them the "Sandwich Islands" in honor of John Montagu, 4th Earl of Sandwich, who was one of his sponsors as the First Lord of the Admiralty. This name was in use until the 1840s when the local name "Hawaii" gradually began to take precedence.
The Hawaiian Islands have a total land area of 6,423.4 square miles (16,636.5 km2). Except for Midway, which is an unincorporated territory of the United States, these islands and islets are administered as Hawaii—the 50th state of the United States.