How to Tell the Difference between Form N-400 and N-600

There are a lot of different USCIS forms and because they’re often referred to by just their form numbers, it can be difficult to remember which is which.

Form N-400 and N-600 are both forms that have to do with US citizenship. But they have two very different purposes.

Form N-400 is used by green card holders to apply for citizenship through a process called naturalization.

Whereas, form N-600 is used by people who are already citizens, but do not have proof of their citizenship.

Are you interested in becoming a U.S. citizen through naturalization? Visit to see if you’re ready to apply for citizenship with form N-400!

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