How Does a Territory Become a State?
Thirty-two U.S. territories have already become states. How did they do it? What is the process for a territory to become a state?
The U.S. Constitution has the simple answer:
New States may be admitted by the Congress into this Union; but no new States shall be formed or erected within the Jurisdiction of any other State; nor any State be formed by the Junction of two or more States, or parts of States, without the Consent of the Legislatures of the States concerned as well as of the Congress.
The big part of this sentence is, New States may be admitted by the Congress into this Union. In other words, Congress can make a new State at any time, without any other requirements.
Changing State Borders
The rest of the sentence explains that Congress cant make a new State within a State without permission from the State or States in question. So Congress couldnt make Northern Colorado into an independent State without permission from Colorados legislature.
Read more:
https://www.puertoricoreport.com/how-does-a-territory-become-a-state/#.W_-8cdtKjRY