A child can, under certain circumstances, derive U.S. citizenship automatically through the naturalization of a parent. The exact terms of this depend upon the laws in place when certain key events occured. In most cases, you need to have already held U.S. lawful permanent residence (a green card) in order to derive U.S. citizenship.
Don't confuse this with the other method of gaining automatic citizenship even if born outside the U.S., described in U.S. Citizenship for Children by Birth to Citizen Parents (Acquisition).
Overview of Relevant Citizenship Derivation Laws
Here's a brief summary of the various citizenship derivation laws that have applied over the years (contact an immigration attorney for details and exceptions):
- Parents naturalized before May 24, 1934: You derive citizenship if either parent naturalized prior to your 21st birthday and you held a green card at the time. You must have been a biological child, not adopted or a stepchild.
- Parents naturalized between May 24, 1934 and January 12, 1941: You derive citizenship if both your parents naturalized prior to your 21st birthday and you had a green card at the time. If only one parent naturalized before you turned 21, you derived U.S. citizenship if you already had a green card for five years at that time.
- Parents naturalized between January 13, 1941 and December 23, 1952: You derive citizenship if you held a green card and both parents naturalized before your 18th birthday; or one parent naturalized but the other parent was dead, or your parents were legally separated and the parent with legal custody of you naturalized.
- Parents naturalized between December 24, 1952 and October 4, 1978: You derive citizenship if you were unmarried, received a green card before your 16th birthday, and both parents naturalized. Or, if only one parent naturalized, you can derive citizenship if the other parent was dead, or your parents were legally separated and the parent with legal custody of you naturalized. You must have been a biological child, not adopted or a stepchild.
- Parents naturalized between October 5, 1978 and February 26, 2001: You derive citizenship if one of your parents was a U.S. citizen when you were born, never ceased to be a citizen, and the other parent was naturalized before your 18th birthday; or the naturalization of both parents occurred before your 18th birthday; and you were unmarried and held a green card at the time.
- Parents born in U.S. or naturalized between February 27, 2001 and the present: You derive citizenship if one of your parents was born in the U.S. or if one of your parents naturalized prior to your 18th birthday and while you were living in the U.S. in the legal and physical custody of that parent, provided you already had a green card (lawful permanent residence). Both biological and adopted children qualify under this law. This allows some children to become U.S. citizens the minute they receive a green card through a U.S. citizen parent.
Applying for Proof of U.S. Citizenship
Although derivation of citizenship is automatic, you'll probably want to have some proof of the person's new status as a U.S. citizen.
To apply for such proof, the child or the naturalized parent needs to fill in USCIS Application for Certificate of Citizenship or Form N-600, along with various documents. The form, instructions, and the latest fee can be found on the N-600 page of the USCIS website, or you might wish to hire an attorney to help.
The child can also apply to the U.S. State Department for a U.S. passport.