If your child is a lawful permanent resident (green card holder) under 18 and is living with you, your child may automatically become a U.S. citizen the moment you naturalize — no separate citizenship application required. This happens under the Child Citizenship Act of 2000, codified at Immigration and Nationality Act (INA) section 320. The citizenship is automatic, but proving it to a passport agency, school, or employer is not — for that, you file Form N-600 with U.S. Citizenship and Immigration Services (USCIS) to get a Certificate of Citizenship.
How automatic citizenship works under INA 320
A child generally acquires U.S. citizenship automatically, without any application, on the date all of the following are true at the same time, and before the child turns 18:
At least one parent is a U.S. citizen — by birth or through naturalization (this includes an adoptive parent in qualifying adoption cases).
The child is under 18 years of age.
The child is a lawful permanent resident — meaning the child already holds a green card.
The child is residing in the United States in the U.S. citizen parent's legal and physical custody.
"Legal custody" refers to who has responsibility and authority for the child under law (which can matter in divorce or separation situations); "physical custody" means the child is actually living with that parent. USCIS does not require the citizen parent to have sole legal custody in every case, but custody questions can get complicated in blended families, so if your situation involves shared custody, a court order, or a non-citizen co-parent, it's worth getting individualized advice.
This framework generally applies to children who meet all the requirements on or after February 27, 2001, the date the Child Citizenship Act took effect. If your child turned 18 before that date, or before meeting all the requirements, older rules (former INA 321 and 320) may apply instead — USCIS's Policy Manual covers those transition cases separately.
Timing matters. If your child turns 18 before you naturalize, or before the child becomes a lawful permanent resident, the automatic provision no longer applies to that child. There is no retroactive fix — an older child in that position would generally need to pursue citizenship on their own, if eligible, through the standard naturalization process. If your child is approaching 18 and you are in the process of naturalizing, talk to USCIS or an immigration attorney promptly about the order and timing of these steps.
How this works for adopted children
Many internationally adopted children qualify for the same automatic citizenship under INA 320, using the same four conditions above, but with an added wrinkle: the adoption must be full and final before the child turns 18, and how (and when) that adoption became final affects whether citizenship is truly automatic.
IR-3 or IH-3 visa (adoption finalized abroad, with the required parental contact before or during the adoption): if the child otherwise meets the INA 320 requirements — is a lawful permanent resident under 18, residing in the U.S. in the citizen parent's legal and physical custody — USCIS generally issues a Certificate of Citizenship automatically once the requirements are met, often without a separate application.
IR-4 or IH-4 visa (adoption not yet final when the child entered the U.S., or pre-adoption requirements still pending): citizenship is usually not automatic in the same way. The adoption typically needs to be finalized in the United States first, and the family may need to take additional steps — including filing Form N-600 with supporting adoption evidence — before a Certificate of Citizenship will issue.
Because adoption visa categories and Hague Convention procedures affect this analysis directly, check the current USCIS adoption guidance for your child's specific visa type, and confirm with USCIS or a qualified immigration attorney before assuming citizenship is automatic in an adoption case.
Automatic citizenship vs. proving it: Form N-600
Automatic citizenship under INA 320 is a legal status — it exists whether or not any paperwork is filed. But in practice, your child needs a document to prove it: for a U.S. passport application, a REAL ID, school enrollment, or many other purposes. That document is a Certificate of Citizenship, obtained by filing Form N-600, Application for Certificate of Citizenship, with USCIS.
Confirm your child meets all four INA 320 requirements as of a specific date (usually the date you take the Oath of Allegiance at naturalization, if your child was already a lawful permanent resident and living with you at that time).
Gather evidence: your Certificate of Naturalization, the child's green card, proof the child resides with you (school records, medical records, a lease or utility bill in your name at the same address), and — for adopted children — the final adoption decree and entry visa documentation.
File Form N-600 with USCIS. Check the current filing fee, whether online or paper filing is available, and current processing times on the USCIS N-600 page and the USCIS Fee Schedule, since these change over time and this article does not quote a fee.
Some N-600 applicants must appear for an interview and take the Oath of Allegiance, depending on age and other case-specific factors; USCIS will notify you if this applies.
Keep the resulting Certificate of Citizenship in a safe place — like a passport, it is expensive and slow to replace if lost, and it's often the easiest way to later obtain a U.S. passport for the child.
There is no deadline to file Form N-600 — citizenship under INA 320 does not expire or need to be "claimed" by a certain date. But delaying the paperwork can delay getting a U.S. passport, enrolling in certain programs, or proving status for a job, so most families file as soon as the requirements are met.
N-600 vs. N-600K: know which one applies
These two forms are easy to confuse but serve very different situations:
Form N-600 is for a child (or adult) who already acquired or derived U.S. citizenship automatically — including through INA 320 — and who is living in the United States. It documents citizenship that already legally exists.
Form N-600K is a citizenship application under INA 322 for a child who lives outside the United States, filed by a U.S. citizen parent (or, in some cases, based on a U.S. citizen grandparent's physical presence in the U.S.). Unlike INA 320, citizenship is not automatic under this pathway — the child must come to the U.S. temporarily and appear for an interview, and (for a child age 14 or older) take the Oath of Allegiance, before USCIS grants citizenship and issues a certificate.
If your child already lives with you in the United States as a lawful permanent resident, N-600 (not N-600K) is almost always the right form once the child qualifies. Filing the wrong form can cause delays, so double-check your child's residence and status before submitting, and confirm the current version of each form on uscis.gov.
Common situations that complicate automatic citizenship
Divorced or separated parents: if the naturalizing parent does not have legal custody, or the child does not actually live with that parent, the automatic provision may not apply until custody and residence align with the requirements.
Child living outside the U.S. temporarily: brief absences (like a vacation) generally don't break "residing in the United States," but an extended stay abroad could raise questions — keep records of the child's actual residence.
Step-parent naturalizing (not a biological or qualifying adoptive parent): a step-parent's naturalization alone does not confer automatic citizenship on a stepchild under INA 320 unless there is also a qualifying adoption.
Child turning 18 soon: if your naturalization interview or oath ceremony could be delayed, and your child is close to 18, ask USCIS about scheduling — the requirements must all be met before the 18th birthday.
Beware of notario and immigration-consultant fraud
Only an attorney licensed to practice law or a representative accredited by the Department of Justice may lawfully give legal advice or charge for help with an immigration case in most states. A "notario público," immigration consultant, or unlicensed "visa expert" is not the same as a lawyer and cannot represent your family before USCIS. File directly with USCIS using official forms from uscis.gov, and if you want help, verify credentials before paying anyone. You can find free or low-cost, accredited help through the Department of Justice's list of recognized organizations and accredited representatives.
This article is general information, not legal advice, and does not create an attorney-client relationship. Because custody, adoption, and timing details can change the outcome, consider consulting a qualified immigration attorney or a DOJ-accredited representative about your child's specific situation.
Do I have to apply for my child's citizenship, or does it happen automatically?
If your child meets all the requirements, citizenship happens automatically by operation of law the moment the last condition is met (usually the day you naturalize). You don't file anything to "get" the citizenship itself. But you should file Form N-600 to get a Certificate of Citizenship, which is the official document proving it happened.
My child is 19. Is it too late?
Yes, for automatic citizenship under INA 320 the child must have been under 18 and met all the requirements before turning 18. If your child was already 18 or older when you naturalized, they generally need to pursue citizenship on their own through the regular naturalization process (Form N-400), if eligible, rather than through this automatic provision. An immigration attorney can review the exact dates in your case.
Does this work if only one parent naturalizes and the other parent is not a citizen?
Often yes. The law generally requires only one parent to be a U.S. citizen, but the child must be residing in that citizen parent's legal and physical custody. How legal custody is evaluated can depend on the family's situation, including divorce, separation, or sole vs. joint custody arrangements, so review the current USCIS Policy Manual or talk to an immigration attorney or DOJ-accredited representative if custody is not straightforward.
Is my adopted child automatically a citizen the same way?
Many adopted children qualify under the same INA 320 framework, but it depends on the adoption being full and final before age 18 and on how the child entered the U.S. Children who entered on an IR-3 or IH-3 visa (adoption finalized abroad) are typically covered automatically once the other requirements are met, and USCIS generally issues the Certificate of Citizenship without a separate application in those cases. Children who entered on an IR-4 or IH-4 visa (adoption not yet final abroad) usually need the adoption finalized in the U.S. first, and the family may need to take additional steps. Check current USCIS adoption guidance for your exact category.
What's the difference between Form N-600 and Form N-600K?
Form N-600 is filed for a child (or adult) who already acquired or derived citizenship automatically and is living in the United States — it simply documents citizenship that already exists. Form N-600K is a different process, used under INA 322, for a child of a U.S. citizen parent who lives outside the United States; that process requires the child to come to the U.S. temporarily and be interviewed, and (for a child age 14 or older) to take the Oath of Allegiance before citizenship is granted.
This article is general legal information, not legal advice, and may not reflect the most current law or the law in your jurisdiction. Laws vary by state and change over time. For advice about your specific situation, consult a licensed attorney.
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