Oahu (oʊˈɑːhuː) (Hawaiian: Oʻahu (oˈʔɐhu)) is the third-largest of the Hawaiian Islands. The island of O’ahu and the Northwestern Hawaiian Islands constitute the City and County of Honolulu. The state capital, Honolulu, is on Oʻahu's southeast coast. Oʻahu has a population of 995,638, up from 953,207 in 2010 (approximately 70% of the total 1,455,271 population of the U.S. state of Hawaii, with approximately 81% of those living in or near the Honolulu urban area).
The Island of Oahu in Hawaii is often nicknamed (or translated as) "The Gathering Place". The translation of "gathering place" was suggested as recently as 1922 by Hawaiian Almanac author Thomas Thrum. It has been speculated that Thrum ignored or misplaced the okina because the Hawaiian phrase "o ahu" could be translated as "gathering of objects" (o is a subject marker and ahu means "to gather"). The term Oʻahu has no confirmed meaning in Hawaiian, other than that of the place itself.
The island has been inhabited since at least the 3rd century A.D. The 304-year-old Kingdom of Oʻahu was once ruled by the most ancient aliʻi in all of the Hawaiian Islands. The first great king of Oʻahu was Maʻilikūkahi, the lawmaker, who was followed by many generations of monarchs. Kualiʻi was the first of the warlike kings and was succeeded by his sons. In 1773, the throne fell upon Kahahana, the son of Elani of Ewa. In 1783, Kahekili II, King of Maui, conquered Oʻahu, deposed the reigning family, and made his son, Kalanikūpule, king of O'ahu, turning O'ahu into a puppet state. Kamehameha the Great conquered Kalanikūpule's forces in the Battle of Nuʻuanu. Kamehameha founded the Kingdom of Hawaiʻi with the conquest of Oʻahu in 1795. Hawaiʻi was not unified until the islands of Kauaʻi and Niʻihau surrendered under King Kaumualiʻi in 1810. Kamehameha III moved his capital from Lāhainā, Maui to Honolulu, Oʻahu in 1845. ʻIolani Palace, built later by other members of the royal family, still stands, and is the only royal palace on American soil.