Article Seven of the United States Constitution describes the process by which the entire document is to be ratified and take effect.
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The Ratification of the Conventions of nine States, shall be sufficient for the Establishment of this Constitution between the States so ratifying the Same.
Background
In 1788, when New Hampshire became the ninth state to ratify, Virginia, New York, North Carolina and Rhode Island remained. Virginia and New York were the most populous and most wealthy American states, respectively. The Congress, as established under the Articles of Confederation, chose March 4, 1789 as the day "for commencing proceedings under the Constitution." Virginia and New York ratified the Constitution before that time; North Carolina and Rhode Island ratified later, after the new government took power in the remaining eleven states.
The Constitution was ratified by the states in the following order: