"51st state", in post-1959 American political discourse, is a phrase that refers to areas or locales that are—seriously or facetiously—considered candidates for U.S. statehood, joining the 50 states that presently compose the United States. The phrase has been applied to external territories as well as parts of existing states which would be admitted as separate states in their own right.
Voters in the District of Columbia and Puerto Rico have both voted for statehood in referendums. As statehood candidates, their admission to the Union requires congressional approval. American Samoa, Guam, the Northern Mariana Islands, and the United States Virgin Islands are also U.S. territories and could potentially become U.S. states.
The phrase "51st state" sometimes has international political connotations not necessarily having to do with becoming a U.S. state. The phrase "51st state" can be used in a positive sense, meaning that a region or territory is so aligned, supportive, and conducive with the United States, that it is like a U.S. state. It can also be used in a pejorative sense, meaning an area or region is perceived to be under excessive American cultural or military influence or control. In various countries around the world, people who believe their local or national culture has become too Americanized sometimes use the term "51st state" in reference to their own countries.Before Alaska and Hawaii became states of the United States in 1959, the corresponding expression was "the 49th state".