National Hawaii Day is observed worldwide every July 5 to recognize Hawaii as the 50th and final state to join the United States. Established by National Day Calendar, this day celebrates Hawaii's unique status as one of two non-contiguous U.S. states and the only island state, comprised of 137 volcanic islands, with eight main islands including Oʻahu and Maui. The holiday honors the history of Hawaii, which was first settled by Polynesians between 1000 and 1200 CE, and later unified under the Kingdom of Hawaii established by Kamehameha in the late 18th century. Hawaii became a U.S. territory in 1898 and achieved statehood on August 21, 1959, following a campaign led by Hawaii-born descendants of immigrant laborers. National Hawaii Day is part of the National State Days project, which celebrates each state's history and culture in the order they joined the Union.