who has the right to admit new states
Admission to the Union The Admission to the Union Clause of the United States Constitution, oftentimes called the New States Clause, and found at Article IV, Section 3, Clause 1, authorizes the Congress to admit new states into the United States beyond the thirteen already in existence at the time the Constitution went into effect.
New England Vermont was admitted to statehood in 1791 after settling a dispute with New York. The territory of Maine had been a part of Massachusetts, but it was granted statehood on March 15, 1820 as part of the Missouri Compromise.[45] Today, New England is defined as the six states of Maine, Vermont, New Hampshire, Massachusetts, Rhode Island, and Connecticut.[5]