A state of the United States is one of the 50 constituent entities that shares its sovereignty with the federal government. Americans are citizens of both the federal republic and of the state in which they reside, due to the shared sovereignty between each state and the federal government. Kentucky, Massachusetts, Pennsylvania, and Virginia use the term commonwealth rather than state in their full official names. States are the primary subdivisions of the United States. They possess all powers not granted to the federal government, nor prohibited to them by the Constitution of the United States. In general, state governments have the power to regulate issues of local concern, such as regulating intrastate commerce, running elections, creating local governments, public school policy, and non-federal road construction and maintenance. Each state has its own constitution grounded in republican principles, and government consisting of executive, legislative, and judicial branches. All states and their residents are represented in the federal Congress, a bicameral legislature consisting of the Senate and the House of Representatives. Each state is represented by two senators, and at least one representative, while the size of a state's House delegation depends on its total population, as determined by the most recent constitutionally mandated decennial census. Additionally, each state is entitled to select a number of electors to vote in the Electoral College, the body that elects the President of the United States and Vice President of the United States, equal to the total of representatives and senators in Congress from that state. Article IV, Section 3, Clause 1 of the Constitution grants to Congress the authority to admit new states into the Union. Since the establishment of the United States in 1776, the number of states has expanded from the original 13 to 50. Each new state has been admitted on an equal footing with the existing states.

List of U.S. states

The following table is a list of all 50 states and their respective dates of statehood. The first 13 became states in July 1776 upon agreeing to the United States Declaration of Independence, and each joined the first Union of states between 1777 and 1781, upon ratifying the Articles of Confederation, its first constitution. (A separate table is included below showing <abbr title="Articles of Confederation">AoC ratification dates.) These states are presented in the order in which each ratified the 1787 Constitution and joined the others in the new (and current) federal government. The date of admission listed for each subsequent state is the official date set by Act of Congress.

Articles of Confederation ratification dates

The Second Continental Congress approved the Articles of Confederation for ratification by the individual states on November 15, 1777. The Articles of Confederation came into force on March 1, 1781, after being ratified by all 13 states. On March 4, 1789, the general government under the Articles was replaced with the federal government under the present Constitution.