It’s a United States... Since the word "united" begins with a consonant sound ("you"), we use the article “a”.
It’s a United States... Use "a" before nouns that begin with a consonant sound, even if the first letter is a vowel. Since the word "united" begins with a consonant sound ("you"), we use the article “a”.
How can I become a United States citizen?
How can I become an United States citizen?
Remember, it's the pronunciation of the following word, not the spelling, which is important.
My father served as a United States senator from 2009 to 2018.
It was a United States Army program to develop a light scout helicopter.
The case can be appealed to a United States court of appeal.
Similarly, we say a "a US official" (not “an US official”).
My mother is a US official.
A partial list of words that begin with the vowel “u” and take the article “a”: