The individual cities, counties, and states within the United States have established borders. We also have firm definitions of our geographic regions, such as the Midwest and the Northeast. Unfortunately, we don’t have such fixed boundaries for how to abbreviate United States. In fact, the sheer number of conflicting guidelines can make you feel like you’ve driven right off the (grammar) map!
Much of this confusion stems from differences between the primary style manuals, as demonstrated below.
The U.S. Government Printing Office Style Manual
The U.S. Government Printing Office Style Manual says that United States should be spelled out unless it is used as an adjective for Government (intentionally capitalized), a government agency, or a general noun, in which case the abbreviation should include periods. However, if the sentence contains the name of another country, the abbreviation should not be used even if United States is used as an adjective.1
The Beatles arrived in the United States in 1964.
The U.S. Government mints coins in Colorado, Pennsylvania, California, and New York.
The U.S. Supreme Court is in recess.
Farmers account for two percent of the U.S. population.
All United States citizens need a passport to visit Canada.
The Chicago Manual of Style
The Chicago Manual of Style (Chicago style) says that both the United States and the abbreviation US can be used as a noun; however, the abbreviation should only be used as a noun if “the meaning is clear from [the surrounding] context.”2
Like the U.S. Government Printing Office, Chicago style recommends the abbreviation when the United States is used as an adjective. The biggest differences between Chicago style and the U.S. Government Printing Office are (1) Chicago style allows for abbreviation even if the name of another country appears in the sentence3 and (2) Chicago style recommends US unless the document uses periods to abbreviate state names, in which case U.S. is acceptable.4
The Beatles arrived in the United States in 1964. (Or: The Beatles arrived in the US in 1964.)
The US government mints coins in Colorado, Pennsylvania, California, and New York.
The US Supreme Court is in recess.
Farmers account for two percent of the US population.
All US citizens need a passport to visit Canada.
The Associated Press Stylebook
The situation gets even stickier when we add The Associated Press Stylebook (AP style) into the mix because it says that the abbreviation can be used as both a noun and an adjective as long as the abbreviation includes periods within text and excludes periods in headlines. In addition, the Associated Press recommends abbreviating the full name United States of America as USA; however, it doesn’t directly mention in-text or headline usage for USA, so the assumption is that U.S. and US are preferred.5
The Beatles arrived in the U.S. in 1964. (In text)
The Beatles Arrive in the US (Headline style)
The U.S. government mints coins in Colorado, Pennsylvania, California, and New York. (In text)
The US Supreme Court is in Recess (Headline style)
Farmers account for two percent of the U.S. population. (In text)
All U.S. citizens need a passport to visit Canada. (In text)
The Publication Manual of the American Psychological Association
The Publication Manual of the American Psychological Association (APA style) simply says that we can use the abbreviation with periods when United States is acting as an adjective.6
The Beatles arrived in the United States in 1964.
The U.S. government mints coins in Colorado, Pennsylvania, California, and New York.
The U.S. Supreme Court is in recess.
Farmers account for two percent of the U.S. population.
All U.S. citizens need a passport to visit Canada.
MLA Handbook
Lastly, the MLA Handbook from the Modern Language Association of America recommends avoiding abbreviations, so MLA followers should spell out United States whenever possible. If MLA followers choose to use an abbreviation, they should only do so when the abbreviation’s meaning will be clear to the reader, in which case United States can be abbreviated as US without periods. MLA doesn’t differentiate between noun and adjective usage for abbreviations.7
Conclusion
Is your head spinning yet? Mine sure is! But as with all things stylistic, the best course of action is to choose the guideline that best fits your unique content—and then stick with it. Sure, that means that your competitors may write US when you write U.S., but that doesn’t matter nearly as much as maintaining consistency throughout all of your documentation.
References
1. U.S. Government Printing Office Style Manual (Washington, DC: U.S. Government Printing Office, 2008) 222–23.
2. The Chicago Manual of Style, 17th ed. (Chicago: University of Chicago Press, 2017) 10.32.
3. The Chicago Manual of Style, 10.32.
4. The Chicago Manual of Style, 10.4.
5. The Associated Press Stylebook 2020–2022 (New York: The Associated Press, 2020) 305, 306.
6. Publication Manual of the American Psychological Association, 7th ed. (Washington, DC: American Psychological Association, 2020) 154.
7. MLA Handbook, 9th ed. (New York: The Modern Language Association of America, 2021) app. 1; “Does the MLA abbreviate United States U.S. or US?” The MLA Style Center, last modified August 30, 2016.
Updated January 23, 2022