Certificate of Citizenship (Form N-600): Proof for Citizens Through a Parent

Written by the Ellis Porter content team. This article has not been reviewed by an attorney. It is general information, not legal advice.

Part of Ellis Porter’s guide to U.S. citizenship through naturalization.

You may already be a citizen. The question is how to prove it.

Maybe your mom became a citizen when you were 12 and you had a green card at the time. Maybe you were born in another country to an American father. Either way, you might be a US citizen today without ever having filed for it. That surprises a lot of families, and it is good news. The harder part is proving it when a school, an employer, or a passport office asks.

This guide is for people who got citizenship through a parent and now need proof. It covers who qualifies, what a Certificate of Citizenship is, how Form N-600 works, what it costs in 2026, and when a US passport may be the simpler answer. If you naturalized yourself and lost your certificate, that is a different form. See our guide to naturalization certificate replacement cost for that.

What is a Certificate of Citizenship?

A Certificate of Citizenship is a document from USCIS that proves you are a US citizen because of a parent. You request it on Form N-600. It does not grant citizenship. It records citizenship you already have, and it does not expire.

That point matters. The USCIS Policy Manual says a person born abroad who automatically acquires citizenship "is not required to have evidence of such status." You are a citizen either way. The certificate is simply strong, permanent proof.

There are three documents people mix up:

If you are still working toward citizenship on your own, start with our overview of US citizenship requirements instead.

Two ways to become a citizen through a parent

There are two main paths. Lawyers call the first one acquisition and the second one derivation. You do not need the labels, but they help you find the right rules.

Path 1: Born abroad to a US citizen parent (acquisition)

Some children are citizens from the moment they are born, even outside the US. Which rule applies depends on the law in effect on the day you were born. The Policy Manual tells officers to use "the applicable statutory provisions and conditions that existed at the time of the person’s birth."

For a child born on or after November 14, 1986, to married parents, the Policy Manual lists these core rules:

• Both parents are citizens: at least one parent must have lived in the US or one of its outlying possessions before the birth.
• One citizen parent, one noncitizen parent: the citizen parent must have been physically present in the US for at least 5 years, including at least 2 years after turning 14.

Children born to unmarried parents face added rules under INA 309. If the citizen parent is the father, the Policy Manual requires proof of a blood relationship by clear and convincing evidence, a written agreement by the father (unless he has died) to support the child financially until 18, and legitimation, a written acknowledgment of paternity, or a court order before the child turns 18. If the citizen parent is the mother, she must have been physically present in the US for 1 continuous year before the birth.

Older birth dates use older rules with different numbers. If you were born before November 14, 1986, have an attorney check the rule for your birth year.

Path 2: Became a citizen after birth with a green card (derivation)

This is the path most green card families never hear about. Under the Child Citizenship Act, a child born abroad becomes a citizen automatically once all the conditions are true at the same time.

The Policy Manual’s chapter on INA 320 lists them, and all must be met before the child turns 18:

1. The child has a parent who is a US citizen, by birth or through naturalization (including an adoptive parent).
2. The child is under 18.
3. The child is a lawful permanent resident, meaning a green card holder.
4. The child lives in the US in the legal and physical custody of the citizen parent.

The order does not matter. A child who got a green card at 10 and whose father naturalized when the child was 15 became a citizen on the day the last condition was met, as long as the child was living with that parent. A child who got the green card at 17 after the parent had already naturalized works the same way.

Legal and physical custody, in plain terms

Custody is where many N-600 cases get complicated, especially after a divorce. The Policy Manual gives USCIS officers some starting presumptions:

• Married parents are presumed to share legal custody.
• If one parent has died, the surviving parent has legal custody.
• For unmarried parents, the parent the child lives with is generally presumed to have legal custody.

Physical custody means the child actually lived with the citizen parent. The Policy Manual calls it the child’s "principal, actual dwelling place in fact."

Divorce, a custody order that names the other parent, or years living with grandparents can all change the answer. Gather the custody paperwork early.

Stepchildren and adopted children

A stepparent does not pass citizenship. The Policy Manual is direct about this: "the stepchild is not the stepparent’s ‘child’ for purposes of citizenship and naturalization." Visa rules sometimes count stepchildren. Citizenship rules do not.

Adopted children can qualify through an adoptive parent, but the adoption must meet the definitions in INA 101(b)(1)(E), (F), or (G). An attorney should confirm that before you file.

The February 27, 2001 cutoff

The Child Citizenship Act took effect on February 27, 2001. The Policy Manual says "persons who were 18 years of age or older before February 27, 2001, do not qualify for citizenship under current Section 320."

That does not mean older adults are out of luck. Many derived citizenship under the old law, former INA 321. According to Policy Manual Chapter 7, it was stricter. While the child was under 18 and living in the US as a green card holder, one of these had to happen:

• Both parents naturalized.
• One parent naturalized, and the other parent had died.
• The parent with legal custody naturalized after a legal separation.
• The mother naturalized, if the child was born to unmarried parents and paternity was not established by legitimation.

The big difference: under the old law, one parent naturalizing was usually not enough if both parents were alive and married. If you were born before February 27, 1983, and your parents naturalized while you were young, check which law covers you. You may be a citizen and not know it.

Do you need a Certificate of Citizenship, or will a passport do?

For most practical uses, a valid US passport works as proof. Under 22 USC 2705, a passport issued to a citizen has "the same force and effect as proof of United States citizenship" as a Certificate of Citizenship or Naturalization. The same statute gives that weight to a Consular Report of Birth Abroad.

So how do you choose? Here is how the options compare:

Many families get a passport first because it doubles as a travel document. The certificate earns its cost when you want a permanent record that never lapses, when a passport application has been delayed or questioned, or when your case rests on custody or old-law facts that you want USCIS to decide once.

A note for green card holders: if you got your green card as a child and are now planning a green card renewal, pause first. Ask whether you may have already become a citizen through a parent. It is worth checking before you spend money renewing a status you may have outgrown.

How to apply for a Certificate of Citizenship with Form N-600

Here is the process, step by step.

1. Confirm the path. Work out which path fits you (at birth or after birth) and which law applied at the time. This drives your evidence.
2. Gather your documents. See the evidence list below.
3. File Form N-600. You can file online through a USCIS account or by mail to the lockbox listed on the form page. The N-600 page says you cannot currently file online if you are applying from outside the US, requesting a fee waiver, or filing on your own behalf as a member or veteran of the US military. For a child under 18, a US citizen parent or legal guardian must file.
4. Attend biometrics. Applicants in the US receive an appointment at a local Application Support Center for photographs.
5. Attend the interview. Most applicants are interviewed. USCIS may waive it if its records already prove eligibility.
6. Take the oath, if required. USCIS gives the Oath of Allegiance before issuing the certificate. It generally waives the oath for children under 14.

Evidence USCIS expects

The Policy Manual lists these documents, as they apply to your case:

• Your birth certificate or birth record
• Your parents’ marriage certificate, and proof that any earlier marriages ended
• Proof of your parent’s US citizenship, such as a birth certificate, naturalization certificate, or passport
• Legitimation documents, if you were born to unmarried parents
• Legal custody papers, in divorce, separation, or adoption cases
• Proof that you lived with the citizen parent while you were under 18
• Your green card or other proof of permanent residence
• A full adoption decree, if adopted
• Proof of any legal name changes
• Official military orders, if they apply

For birth-abroad cases, expect to prove your citizen parent’s past physical presence in the US. School transcripts, tax records, and employment records are common sources.

What Form N-600 costs in 2026

As of the USCIS fee schedule, Form G-1055, edition 10/26/26:

The military exemption does not cover service members’ children. The fee schedule says so plainly. If you are asking for a fee waiver, file on paper, since online filing is not available for fee waiver requests.

How long does an N-600 take?

Processing times change month to month and differ by field office. Check the current estimate for Form N-600 on the USCIS processing times tool before you plan around a date.

If you need proof sooner, for a job or a trip, ask an attorney if applying for a passport first makes more sense for your situation.

Children living abroad: Form N-600K

A child who lives outside the US usually cannot use INA 320, because that law requires living in the US with a green card. Under INA 322, a citizen parent can apply on the child’s behalf with Form N-600K, and the process must be completed before the child turns 18, as described in Policy Manual Chapter 5. The fee is the same as Form N-600.

Common mistakes that slow N-600 cases

• Filing under the wrong law. Using the 2001 rules when you turned 18 before February 27, 2001, or the reverse.
• Assuming a stepparent counts. It does not, unless there was a qualifying adoption.
• Thin custody evidence. After a divorce, USCIS needs to see who had legal custody and where you actually lived.
• Missing proof of the parent’s physical presence. Common in birth-abroad cases, and often the hardest part to rebuild decades later.
• Filing when you already have a valid passport. You may not need the certificate. Decide on purpose.

If you hold another nationality, you may also want to read about what countries allow dual citizenship before you rely on any document for travel.

Have your situation reviewed before you file

Citizenship through a parent often turns on dates, custody papers, and which law applied in a given year. A careful review before you file can save months and a nonrefundable fee. An Ellis Porter attorney can review your family history, tell you which path likely applies, and help you decide between a passport and Form N-600. Learn more about our naturalization and citizenship services.

This article is general information, not legal advice, and does not create an attorney-client relationship. Citizenship rules depend on dates and facts that vary by family. Fees and processing times change; confirm current details with USCIS and consult a licensed immigration attorney about your situation.

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