Hawaii is a state in the Western United States, located in the Pacific Ocean about 2,000 miles (3,200 km) from the U.S. mainland. It is an island state and an archipelago, consisting of 137 volcanic islands that comprise almost the entire Hawaiian archipelago. Hawaii is the only U.S. state that is situated entirely on an archipelago, and the only state not geographically connected with North America. The capital of Hawaii is Honolulu, located on the island of Oahu. Hawaii became the 50th U.S. state on August 21, 1959.