Admission to the Union

Admission to the Union is provided by the Admissions Clause of the United States Constitution in Article IV, Section 3, Clause 1, which authorizes the United States Congress to admit new states into the Union beyond the 13 states that already existed when the Constitution came into effect. The Constitution went into effect on June 21, 1788, in the nine states that had ratified it, and the U.S. federal government began operations under it on March 4, 1789, when it was in effect in 11 out of the 13 states. Since then, 37 states have been admitted into the Union. Each new state has been admitted on an equal footing with those already in existence.

Of the 37 states admitted to the Union by Congress, all but six have been established within existing U.S. organized incorporated territories. A state that was so created might encompass all or part of a territory. When the people of a territory or a region have grown to a sufficient population and made their desire for statehood known to the federal government, Congress in most cases has passed an enabling act, authorizing the people of that territory or region to frame a proposed state constitution as a step toward admission to the Union. In many instances, an enabling act would detail the mechanism by which the territory would be admitted as a state after the ratification of their constitution and the election of state officers.

The broad outline for the process was established by the Land Ordinance of 1784 and the 1787 Northwest Ordinance, both of which predate the U.S. Constitution.