With the adoption by the 2nd Continental Congress of the Declaration of Independence, 13 independent British colonies became states under the US Congress.
What came first? Id say Congress came first.
Mississippi, Florida, Alabama, Louisiana, Arkansas, Tennessee, Missouri, Oklahoma... Were all U.S. territory
The Louisiana Purchase, was made by United States
Florida was purchase from Spain by United States
And South Carolina, North Carolina, Virginia, Georgia ceded any pre revolution colonial claims to the area that became Tennessee Alabama, and part of Mississippi to the United States