List of state partition proposals in the United States

Numerous state partition proposals have been put forward since the 1776 establishment of the United States that would partition an existing U.S. state or states so that a particular region might either join another state or create a new state. Article IV, Section 3, Clause 1 of the United States Constitution, often called the New States Clause, grants to the United States Congress the authority to admit new states into the United States beyond the thirteen that existed when the Constitution went into effect (June 21, 1788, after ratification by nine of the thirteen states).

Source: Wikipedia — List of state partition proposals in the United States (CC BY-SA 4.0)