When the United States was officially established in the wake of the Revolutionary War, the Founding Fathers understood that the new nation would eventually expand beyond its original 13 states. While they could not predict how large the country would become, they knew pioneers would settle the vast frontier that lay before them and that new states would join the Republic.
With the nation’s future in mind, the framers of the US Constitution wrote Article IV, Section 3:
New States may be admitted by the Congress into this Union; but no new State shall be formed or erected within the Jurisdiction of any other State; nor any State be formed by the Junction of two or more States, or Parts of States, without the Consent of the Legislatures of the States concerned as well as of the Congress.
The Congress shall have Power to dispose of and make all needful Rules and Regulations respecting the Territory or other Property belonging to the United States; and nothing in this Constitution shall be so construed as to Prejudice any Claims of the United States, or of any particular State.
Under Article IV, Section 3, Congress was given the authority to add new states to the Union, but new states could not be created inside the borders of existing states. New York, for instance, could not simply declare New York City a separate state.
Delaware became the first state to join the Union on December 7, 1787. The US eventually expanded to 50 states, with Arizona, Alaska, and Hawaii becoming the final three states admitted on February 14, 1912, January 3, 1959, and August 21, 1959, respectively.
Additionally, Article IV, Section 3 recognized that the United States is made up of more than just states: There are also territories and other lands – like national parks - which Congress has the power to regulate or sell.
