The Two Lone States
Out of the fifty U.S. states, forty-eight are connected together in one large block. But two states stand apart: Hawaii and Alaska. Neither of them shares a land border with any other U.S. state. For this reason, the other forty-eight are called the "contiguous" states.
Hawaii: An Island State
Hawaii is set apart by the ocean. It is a group of islands far out in the Pacific Ocean, around 2,000 miles from the mainland. Surrounded entirely by sea, Hawaii naturally has no land border with anything at all. It is the only U.S. state made up entirely of islands.
Alaska: Separated by Canada
Alaska is a different case. It is firmly part of the North American mainland, but it sits in the far northwest, beyond the rest of the United States. The country of Canada lies in between, separating Alaska from the nearest U.S. state. So while Alaska does have land borders, those borders are with Canada, not with another American state.
Source
This article was written using information from Wikipedia.