Oʻahu, sometimes written Oahu, is the third-largest and most populated island of the Hawaiian Islands and of the U.S. state of Hawaii. The state capital, Honolulu, is on Oʻahu's southeast coast. The island of Oʻahu and the uninhabited Northwestern Hawaiian Islands constitute the City and County of Honolulu. In 2024, Oʻahu had a population of 998,747, down from 1,016,494 in 2020.