United States’ is the correct possessive form of the United States because states is plural, so we must use a plural possessive. E.g., “The United States’ president.” Furthermore, United States’s is incorrect because you cannot use singular possessives with plural words.
The following chart shows the different forms of the word United States. As you can see, although as an entity, the United States is singular because there is only one. Therefore, when using the non-possessive version, you must structure the verbs as though the sentence is singular.
| Singular | United States |
| Plural | NA |
| Singular possessive | NA |
| Plural possessive | United States’ |
However, when using the possessive version, you must use the plural possessive because the possessive is attached to the plural word states.
As shown in these examples:
- Singular: The United States donates money to causes worldwide.
- Plural possessive: The United States’ donations help fund conservation projects worldwide.
The non-possessive sentence has the verb donate with an “s” to show that the United States is singular. However, in the possessive example, the apostrophe is at the end of United States with no additional “s” to show that the word states is plural.
Now that you have learned the basics about using the possessive version of the United States, please keep reading to learn more about how to use it in your writing.
United States’
The term United States’ is the only correct possessive form for the United States of America. Therefore, you use it to indicate that something belongs to the United States.
The types of things you use the possessive form, United States’, for vary tremendously. However, some common things include places or geographical features.
- The United States’ national parks are among the world’s most diverse.
Furthermore, you can use the possessive form to refer to people from the US and actions or policies implemented by the US.
- The United States’ diversity is one of its most vital advantages.
- Many have been unhappy with the United States’ decisions on foreign policy over the last thirty years.
Also, considering that United States’ is the only possessive form, it is the form that the Chicago Manual of Style and AP Style use.
In addition, if you shorten the word United States to the U.S., you should also use the plural possessive.
- The U.S.’ most populous city is New York.
United States’s
The term United States’s is incorrect, and you should not use it in any piece of writing.
The reason that it is wrong is that the word states is a plural word. Therefore, it is incorrect to use a singular possessive with a plural word.
- Incorrect: The United States’s constitution was created in 1787.
- Correct: The United States’ constitution was created in 1787.