There are 50 states in the United States of America. The 49th and 50th states added to the Union, Alaska and Hawaii, both achieved statehood in 1959; Alaska became a state in January, and Hawaii in August.
The first three states to join the Union, Delaware, Pennsylvania and New Jersey, all achieved statehood on different days in December of 1787. Georgia and Connecticut followed in January of 1788. Massachusetts, Maryland, South Carolina, New Hampshire, Virginia and New York all joined in the same year. The 12th state, North Carolina, joined a little over a year later in 1789, and the 13th state, Rhode Island, joined in 1790. Vermont, Kentucky and Tennessee joined before the turn of the century, bringing the total number of states to 16 as of 1800. Twenty-nine states were added in the 19th century. In addition to Alaska and Hawaii, Oklahoma, New Mexico and Arizona also became states in the 20th century.