The USA is a federal republic, which has 50 states at the present. The contiguous United States (the "Lower 48") are made of 48 states on the North American mainland. There are two non-contiguous states in Alaska and Hawaii. They became the final Unionists in 1959. Although the U.S. also is home to the District of Columbia (Washington, D.C.) and some territories (such as Puerto Rico and Guam), these are not considered as states.