The US Island State is Hawaii, which is a 6 letter word. Hawaii is the 50th and most recent state to have joined the United States, having become a state on August 21, 1959. It is the only U.S. state located in Oceania, the only U.S. state located outside North America, and the only one composed entirely of islands. Hawaii is the 8th-smallest and the 11th-least populous, but the 13th-most densely populated of the 50 states.