As of 2015, the United States of America consists of 50 states. The United States formed in 1776 with 13 states. The 50th state, Hawaii, joined the nation on Aug. 21, 1959.
Article IV, Section 3 of the U.S. Constitution grants Congress the power to admit new states to the Union. It forbids the formation of new states by splitting or merging existing states without the consent of the state legislatures and Congress. The Northwest Ordinance of 1787 outlines the typical path to statehood, in which the federal government oversees a territory directly until the population reaches 5,000 eligible voters. At a population of 60,000, the territory may petition for statehood. Congress votes on the petition, and the president signs it.