Hawaii is the most recent of the 50 U.S. states (joined the Union on August 21, 1959), and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean.
Hawaii’s diverse natural scenery, warm tropical climate, abundance of public beaches and oceanic surrounding, and active volcanoes make it a popular destination for tourists, surfers, biologists, and volcanologists alike.
Hawaii is the 8th-least extensive, the 11th-least populous, but the 13th-most densely populated of the 50 U.S. states. Hawaii's coastline is approximately 750 miles (1,210 km) long, which is fourth in the United States after Alaska, Florida and California.
References:
http://en.wikipedia.org/wiki/Hawaii
http://en.wikipedia.org/wiki/San_francisco