al government have been admitted:
- Vermont, an unrecognized but de facto independent republic until its admission in 179116
- Kentucky, a part of Virginia until its admission in 179216
- Maine, a part of Massachusetts until its admission in 182016 following the Missouri Compromise
- Texas, a recognized independent republic until its admission in 184516
- California, created as a state (as part of the Compromise of 1850) out of the unorganized territory of the Mexican Cession in 1850 without ever having been a separate organized territory itself16
- West Virginia: During the Civil War Virginia had two state governments, a Unionist one and a Confederate one, both claiming to be the legitimate state government of Virginia. West Virginia was created in 1863 by the Unionist state government from areas of western Virginia, after the Confederate state government's 1861 secession of Virginia to the Confederate States of America.
Congress is also under no obligation to admit states even in those areas whose population expresses a desire for statehood. For instance, the Republic of Texas requested annexation to the United States in 1837, but fears about potential conflict with Mexico delayed the admission of Texas for nine years.17
Once established, most state borders have been generally stable, with exceptions including the formation of the Northwest Territory in 1787 and the Southwest Territory in 1790 from various portions of the original states, the cession by Maryland and Virginia of land to create the District of Columbia in 1791 (Virginia's portion was returned in 1847), and the creation of states from other states, including the creation of Kentucky and West Virginia from Virginia, and Maine from Massachusetts. However, there have been numerous minor adjustments to state boundaries over the years due to improved surveys, resolution of ambiguous or disputed boundary definitions, or minor mutually agreed boundary adjustments for administrative convenience or other purposes.16 One notable example is the case New Jersey v. New York, in which New Jersey won roughly 90% of Ellis Island from New York in 1998.18
There are several U.S. territories that might become new states.
Puerto Rico referred to itself as the "Commonwealth of Puerto Rico" in the English version of its constitution, and as "Estado Libre Asociado" (literally, Associated Free State) in the Spanish version.
As with any non-state territory of the United States, its residents do not have voting representation in the federal government. Puerto Rico has limited representation in the U.S. Congress in the form of a Resident Commissioner, a delegate with limited voting rights in the Committee of the Whole House on the State of the Union, and no voting rights otherwise.19
A non-binding referendum on statehood, independence, or a new option for an associated territory (different from the current status) was held on November 6, 2012. Sixty one percent of voters chose the statehood option, while one third of the ballots were submitted blank.2021
On December 11, 2012, the Legislative Assembly of Puerto Rico has enacted a concurrent resolution to request the President and the Congress of the United States to respond diligently and effectively, and to act on the demand of the people of Puerto Rico, as freely and democratically expressed in the plebiscite held on November 6, 2012, to end, once and for all, its current form of territorial status and to begin the process to admit Puerto Rico to the Union as a State.22
The intention of the Founding Fathers was that the United States capital should be at a neutral site, not giving favor to any existing state; as a result, the District of Columbia was created in 1800 to serve as the seat of government. The inhabitants of the District do not have full representation in Congress or a sovereign elected government (they were allotted presidential electors by the 23rd amendment, and have a non-voting delegate in Congress).
Some residents of the District support statehood of some form for that jurisdiction—either statehood for the whole d