Proving citizenship you already have
Some people are already U.S. citizens without knowing it - born abroad to a citizen parent, or automatically naturalised when a parent naturalised while they were a minor green card holder. This process documents that citizenship rather than granting it. A U.S. passport is usually the cheapest proof; a certificate of citizenship on Form N-600 is the formal one.
Who it is for. People who acquired citizenship at birth abroad or derived it through a parent, children abroad of U.S. citizen parents, and citizens who have lost a certificate.
The forms, in order
- 1
Work out whether you acquired or derived citizenship
The rules turn on the law in force at the time of birth or of the parent's naturalisation, and they have changed many times.
- 2
Consider applying for a U.S. passport first
- 3
File Form N-600 for a certificate of citizenship
5.5 months national median in FY 2026.
- 4
For a child living abroad, file Form N-600K instead
The child must come to the United States in lawful status for the interview and oath.
- 5
Replace a lost or incorrect certificate
Where it goes wrong
- A certificate is expensive and slow; a passport proves the same thing for far less.
- The N-600K deadline is the child's eighteenth birthday, with no extensions.
- The military fee exemption on Form N-600 covers the service member only, not their children.
- Getting the applicable law wrong is easy - the transmission rules changed in 1934, 1952, 1978, 1986 and 2000.
What changed in 2025 and 2026
- Passport adjudication has tightened for applicants relying on derived citizenship, with more requests for evidence about the parent's physical presence.
- N-600 processing rose from 2.9 months in FY 2025 to 5.5 months in FY 2026.