Form N-600K: how to apply for US citizenship for your child living abroad
Form N-600K is the only USCIS form that allows a US citizen parent living outside the United States to apply for their child’s citizenship at a USCIS office inside the US.
USCIS Form N-600K – officially titled “Application for Citizenship and Issuance of Certificate Under Section 322” – is a naturalization application, not a request to document citizenship the child already holds.
If you are a US citizen raising a child abroad and that child did not acquire US citizenship at birth, the Form N-600K application for citizenship is the pathway to naturalize them.
USCIS processes the application, interviews you and your child at a US field office, and – if approved – issues a Certificate of Citizenship on the spot.
How N-600K differs from N-600
Form N-600 documents citizenship that a child already has – typically because the child is a lawful permanent resident living inside the US and acquired citizenship automatically under INA Section 320.
N-600K, by contrast, is governed exclusively by INA Section 322 and is built for families living abroad.
What this article covers
Eligibility, the physical presence requirement, how to file, current fees, processing times, and the US tax obligations that begin the moment your child becomes a citizen.
For the 2026 filing season, all tax figures reference tax year 2025 unless noted otherwise.
N-600K vs N-600: which form do you need?
The single biggest difference between N-600 and N-600K is where your family lives – N-600K is exclusively for families residing outside the United States.
The following comparison covers the five factors that determine which form applies.
| Factor | Form N-600K | Form N-600 |
|---|---|---|
| Who files it | US citizen parent living abroad | Child or parent living in the US |
| Where filed | USCIS lockbox in the US, or online | USCIS lockbox in the US, or online |
| Governing law | INA Section 322 | INA Sections 301, 309, and 320 |
| Key requirement | US citizen parent or grandparent meets physical presence test; child resides abroad in parent’s custody | Child already acquired citizenship at birth or automatically as an LPR under INA 320 |
| Age restriction | Child must be under 18 at naturalization | No age restriction |
If the child is already a lawful permanent resident living in the US with a US citizen parent, the child may have acquired citizenship automatically under INA Section 320.
Form N-600 is the correct form to document that status. N-600K applies only when the child lives abroad and has not yet become a citizen.
Who qualifies for Form N-600K? Eligibility requirements explained
A child born abroad to a US citizen parent does not always acquire US citizenship at birth – when they don’t, Form N-600K is the application that naturalizes them.
The following six conditions must all be met under INA Section 322.
- The child must be under age 18 at the time USCIS approves the application and administers the oath of allegiance.
- At least one parent must be a US citizen – by birth or through naturalization. Adoptive parents also qualify.
- The child must be residing outside the United States in the legal and physical custody of the US citizen parent.
- The child must be temporarily present in the United States on a lawful admission – visitor visa, ESTA, or any other valid status – at the time of the interview and naturalization.
- The child must be maintaining that lawful status at the time USCIS adjudicates the application.
- The US citizen parent, or a qualifying US citizen grandparent, must meet the physical presence requirement – five years in the US, at least two after age 14.
The most misunderstood requirement
Number 4 catches many families off guard: the child must physically enter the US and be lawfully present for the interview and oath.
Filing the N-600K form for your child from abroad is only the first step – the child still needs to travel to the US before USCIS can approve the application.
Military exception
Children of US armed forces members stationed abroad under official orders may qualify for an exception under INA Section 322. This provision allows the entire process – including the oath – to take place overseas.
Physical presence requirement: what parents and grandparents must prove
Many expat parents are surprised to learn that if they cannot personally satisfy the physical presence requirement, a qualifying grandparent can step in – making Form N-600K accessible to more families than they realize.
To meet the N-600K parent requirements, you or a qualifying grandparent must show physical presence in one of two ways.
Scenario A – the US citizen parent qualifies personally
The parent must have been physically present in the US or its outlying possessions for at least five years total, with at least two of those years after turning 14.
The time does not need to be continuous. Years spent in the US as a child, student, or worker all count – even time before the parent became a citizen.
Scenario B – grandparent substitution
If the parent cannot meet the five-year threshold, a US citizen grandparent’s physical presence can substitute.
The grandparent must be a US citizen and must meet the same five-year/two-after-14 standard. This provision exists only under INA Section 322 – it is not available for N-600 or for citizenship at birth under INA Section 301.
The N-600K physical presence rule is separate from the FEIE physical presence test, which uses a different 330-day standard. Do not confuse the two.
Age limit and timing: why acting before the child turns 18 is critical
USCIS must approve the N-600K application and the child must take the oath of allegiance before their 18th birthday – missing this deadline means the child loses eligibility under Section 322 entirely.
There is no grace period, no extension, and no exception apart from the military provision under INA Section 322.
The age cutoff applies at the time of naturalization, not at the time of filing.
Filing early does not protect eligibility if processing takes longer than expected.
Because N-600K processing times vary widely by field office and can run several years at the slowest, families should file with enough lead time to absorb delays.
Once a child turns 18, the INA Section 322 pathway closes. Alternative naturalization routes exist for adults, but they require the person to apply on their own behalf and meet different residency and language requirements.
Step-by-step: how to file Form N-600K
Unlike most immigration forms, Form N-600K is submitted to a USCIS lockbox in the United States – not directly to an overseas consulate – before the USCIS field office becomes involved.
The N-600K filing process has nine stages.
- Confirm eligibility under INA Section 322. Review the six requirements in the eligibility section above. If any condition is not met, USCIS will deny the application.
- Download the current Form N-600K from USCIS.gov. The current edition is dated 01/20/25. You can also file online through a USCIS account.
- Complete all sections. The form asks for the child’s information, details about the US citizen parent, and evidence of the parent’s or grandparent’s physical presence in the US.
- Gather supporting documents. See the checklist below.
- Pay the filing fee. The current fee is $1,385 for paper or $1,335 online. Verify the current fee on the USCIS fee schedule before submitting.
- Submit the completed package. Mail to the USCIS lockbox in Phoenix, AZ, or Elgin, IL. Alternatively, file online.
- Attend a biometrics appointment if required. USCIS will notify you if biometrics are needed.
- Arrange the child’s lawful entry into the US. The child needs a valid visa or ESTA for the interview.
- Attend the interview at a USCIS field office. Both the parent and child appear in person. If approved, USCIS administers the oath – waived for children under 14 – and issues the Certificate of Citizenship.
The Form N-600K instructions walk through each section of the form and list all required evidence.
Required documents checklist for N-600K
USCIS officers scrutinize physical presence documentation most heavily – submitting contemporaneous records such as school transcripts and IRS tax transcripts strengthens an N-600K application.
Learning how to fill out N-600K starts with assembling the right supporting package.
Documents required or strongly recommended:
- Child’s foreign birth certificate, with a certified English translation if not in English
- Child’s foreign passport
- Evidence of the US citizen parent’s citizenship – US passport, birth certificate, or naturalization certificate
- Evidence of the parent’s physical presence in the US – tax returns, school transcripts, employment records, military service records
- Evidence of the legal parent-child relationship – marriage certificate, adoption decree, or court order of paternity if applicable
- Two passport-style photographs of the child meeting USCIS specifications
- Filing fee payment via Form G-1450 or G-1650
If a grandparent’s physical presence is being used, include the grandparent’s citizenship documentation and physical presence evidence as well.
N-600K processing time: what to expect in 2025 and 2026
N-600K processing times are not uniform – the USCIS field office where your child will be interviewed can dramatically affect how long the process takes, with the fastest offices taking a few months and the slowest taking several years.
N-600K processing times vary enormously by field office – some complete cases in a few months, others take several years. Check the current estimate for your specific office using the USCIS processing times tool before you file.
Choosing your interview office matters
Because N-600K interviews happen at USCIS domestic field offices – not consulates abroad – the processing time depends on which US city you choose.
When completing the form, you can specify a preferred USCIS office for the interview. Some offices carry significantly longer backlogs than others.
N-600K interview: how to prepare your child and your documents
The N-600K interview takes place at a USCIS field office inside the United States – the child must enter the US on a lawful admission and appear in person with the US citizen parent. If approved, USCIS administers the oath at the same appointment.
Before the interview:
- Review all submitted documents and bring originals of every document included in the application
- Prepare the child to answer basic questions about their identity and family
- Confirm the child’s US visa or entry authorization is valid for the interview date
- Check the specific USCIS office’s requirements in advance – procedures vary by location
- Bring the child’s foreign passport and any additional evidence USCIS requested after filing
What to expect at the interview
Most interviews go smoothly when the documentation is complete.
Officers may request additional evidence of physical presence if the submitted records are sparse. If USCIS cannot approve the application at the interview, the officer will explain what is still needed.
Arriving early, bringing all originals, and confirming the child’s visa status are the most important steps you can take.
Common reasons N-600K applications are denied – and how to avoid them
The single most preventable reason for N-600K denial is submitting insufficient evidence of the US citizen parent’s physical presence in the United States – a gap that careful record-keeping can eliminate entirely.
The most common N-600K application denial reasons are:
- Insufficient physical presence documentation. The parent or grandparent cannot demonstrate five years of physical presence, or the evidence is not contemporaneous.
- Child is 18 or older at time of naturalization. The oath must be administered before the 18th birthday. Processing delays alone can cause this.
- Parent’s citizenship status is unclear. Missing or expired proof of the parent’s own US citizenship.
- Incorrect or outdated form version. USCIS rejects applications filed on superseded editions.
- Missing certified translations. Every document not in English needs a certified translation.
- Failure to establish the parent-child relationship. Adoption cases and children born out of wedlock require additional documentation.
- Child entered the US unlawfully or lost status. The child must be in valid immigration status at the interview.
N-600K for grandparents: when a grandparent’s presence counts
The grandparent physical presence substitution under INA Section 322 is one of the most underutilized provisions in US citizenship law – and one of the most valuable for expat families who have lived abroad for most of their lives.
Under INA Section 322, if the US citizen parent cannot personally satisfy the five-year physical presence requirement, a US citizen grandparent’s physical presence may substitute.
The grandparent must be a US citizen and must have met the same five-year/two-after-14 standard.
Documentation for the grandparent track
The requirements are identical – the grandparent’s school records, tax transcripts, employment records, and other contemporaneous evidence of US presence must be submitted alongside the application.
This provision applies only to the N-600K pathway, not to Form N-600 or to citizenship acquired at birth.
Filing on behalf of a deceased parent
A separate rule allows a US citizen grandparent or legal guardian to file the N-600K application on the child’s behalf if the US citizen parent has died, but only within five years of the parent’s death.
N-600K vs CRBA: which path is right for your family?
A CRBA is typically obtained at or shortly after birth, while N-600K is the right path when the child did not acquire US citizenship at birth – usually because the citizen parent did not meet the physical presence requirements needed to transmit citizenship before the birth.
The following table compares the two pathways.
| Factor | N-600K – Certificate of Citizenship | CRBA – Consular Report of Birth Abroad |
|---|---|---|
| Purpose | Naturalizes a child who did not acquire citizenship at birth | Documents a child who already is a citizen from birth |
| Governing form | USCIS Form N-600K | State Dept Form DS-2029; certificate issued is FS-240 |
| Where obtained | USCIS field office inside the US | US consulate or embassy abroad |
| Child’s age at filing | Under 18 | Must apply before the child’s 18th birthday, like N-600K; recommended promptly after birth |
| Physical presence on parent | Five years, at least two after age 14; grandparent substitution available | Varies based on when the parent and child were born |
| Result document | N-600K citizenship certificate – Certificate of Citizenship | CRBA, Form FS-240 |
Who should use which path
A child who acquired citizenship at birth but was never documented can still get a CRBA before 18 or file N-600 at any age.
N-600K exists specifically for children who did not meet the statutory conditions for citizenship at birth and must be naturalized.
A child with a valid, unexpired US passport or CRBA already has conclusive proof of citizenship. USCIS will deny an N-600K in that case.
The CRBA application is filed at a US consulate or embassy abroad using Form DS-2029, or through the State Department’s online eCRBA portal.
Tax implications when your child becomes a US citizen through N-600K
The moment your child is naturalized as a US citizen through Form N-600K, they become subject to US worldwide income tax obligations – a consequence many expat parents do not fully consider before filing.
Once your child holds N-600K citizenship, the same US tax rules apply as for any other citizen.
The US taxes its citizens on worldwide income regardless of where they live.
Filing thresholds
Your child will have annual US tax filing obligations once their income crosses the dependent filing thresholds for tax year 2025 – and these are much lower for investment-type income than for wages. A dependent must file once unearned income, such as interest, dividends, and trust distributions, exceeds $1,350, or once earned income such as wages exceeds $15,750.
In practice, most minor children don’t earn enough in wages to trigger a filing obligation, but investment income, trust distributions, and foreign bank interest are unearned income and can cross the much lower $1,350 threshold quickly. Unearned income above $2,700 may also be taxed at the parent’s marginal rate under the kiddie tax rules.
Foreign account reporting
If your child’s foreign accounts exceed $10,000 in aggregate at any point during the year, FBAR filing is required. A parent may file on their behalf.
Filing requirements for expat children: what parents need to know
Obtaining a Social Security Number for your newly naturalized child is not optional – it is the foundation of every future US tax filing obligation they will have.
The following requirements apply once citizenship is granted:
- US citizen children abroad must file a US tax return once their unearned income, such as interest, dividends, and trust distributions, exceeds $1,350 for tax year 2025, or once their earned income such as wages exceeds $15,750 for tax year 2025 – both thresholds adjust annually for inflation
- Parents may elect to report a child’s investment income on their own return using Form 8814 if the child’s income consists only of interest and dividends and is below $13,500 for tax year 2025
- Children with foreign financial accounts may have FBAR and FATCA reporting obligations, independent of income thresholds
- An SSN is required for the child to file US tax returns – an ITIN is not appropriate for US citizens, as ITINs are for individuals not eligible for an SSN
Dual citizenship implications for children naturalized through N-600K
Gaining US citizenship through N-600K does not automatically require your child to renounce their other citizenship, but their country of residence may impose its own rules that could affect their status there. The United States generally permits dual citizenship.
What varies by country
Some countries automatically strip citizenship from nationals who acquire another nationality. Others permit dual status indefinitely.
Families should research their country’s rules – and consult local legal counsel – before proceeding with the N-600K application.
Tax obligations remain regardless
US tax obligations apply whether the child holds dual citizenship or not. A US citizen with two passports still files US tax returns on worldwide income and reports foreign financial accounts.
See our dual citizenship guide for a country-by-country overview.
Social Security Number for your child after N-600K approval
A Social Security Number is the single most important document your child needs after receiving their Certificate of Citizenship – without it, they cannot fulfill any US tax or financial reporting obligations.
- After naturalization, apply for a US passport using the Certificate of Citizenship as proof.
- Apply for an SSN at a Social Security Administration office. Some US embassies and consulates can assist from abroad.
- Once the SSN is issued, the child can be included on US tax returns and open US financial accounts.
- The SSN is required for FBAR filings if the child has foreign accounts above the $10,000 aggregate threshold.
N-600K for expats: real-world scenarios and case studies
The grandparent physical presence substitution has saved citizenship applications for dozens of TFX client families where the parent spent most of their life abroad. The following scenarios illustrate how the N-600K process works in practice.
1. US citizen mother in Germany – approved in nine months
A US citizen mother who has lived in Germany for 15 years files Form N-600K for her 10-year-old adopted son. She meets the physical presence requirement through her own childhood years spent in the US – elementary school through high school counts.
The application is approved after a nine-month process at the USCIS field office in Newark.
2. Grandparent substitution saves a Singapore family’s application
A US citizen father living in Singapore cannot meet the physical presence requirement personally because he moved abroad at age 15, leaving him with only one year of US presence after turning 14.
His US citizen mother – the child’s grandmother – qualifies with 30 years of US residence. The grandparent substitution provision under INA Section 322 saves the application.
3. UK family races the 18th birthday deadline
A family in the UK discovers their 17-year-old daughter did not acquire US citizenship at birth, because her US citizen parent fell short of the physical presence requirement before she was born. They file Form N-600K urgently.
Because the USCIS field office they selected had a processing time under six months, the application is approved just before her 18th birthday.
N-600K application fee and cost breakdown
Unlike many USCIS forms, Form N-600K does not require a separate biometrics fee – but always verify current fee requirements on USCIS.gov before submitting payment.
Current filing fee
The USCIS filing fee for Form N-600K is $1,385 for paper or $1,335 for online filing. The $50 difference reflects a discount under 8 CFR 106.1.
Fee waivers and exemptions
Fee waivers may be available for low-income applicants using Form I-912. Waivers are only available for paper filings – USCIS does not process fee waivers online.
There is no fee exemption for adopted children filing Form N-600K. Adopted and biological children pay the same filing fee: $1,385 for paper filing or $1,335 online.
Additional costs to budget for:
- Certified translation fees for foreign-language documents
- Document authentication or apostille costs
- Travel expenses for the child’s trip to the US for the interview
- The child’s US visa application fee, if applicable
Frequently asked questions
Form N-600K is the USCIS application used by a US citizen parent residing abroad to naturalize a foreign-born child under INA Section 322. If approved, USCIS issues a Certificate of Citizenship.
The child must be under 18 at the time of naturalization – not just at filing. USCIS must approve the application and administer the oath before the child’s 18th birthday.
Yes. Under INA Section 322, a US citizen grandparent’s physical presence – five years, at least two after age 14 – may substitute if the parent cannot meet the requirement.
N-600 documents citizenship that already exists, for children who acquired it at birth or automatically under INA Section 320. N-600K naturalizes children living abroad who did not acquire citizenship at birth.
Yes. The child must be temporarily present in the US on a lawful admission for the interview and oath at a USCIS field office.
Tax returns, school transcripts, employment records, military service records, and other contemporaneous evidence of time spent in the US. IRS tax return transcripts are among the most persuasive.
Yes. US citizens are taxed on worldwide income regardless of where they live. As a dependent, your child’s filing threshold depends on the type of income: $1,350 for unearned income such as interest, dividends, and trust distributions, or $15,750 for earned income such as wages, both for tax year 2025.
Processing times vary enormously by USCIS field office – some complete cases in a few months, others take several years. Check the USCIS processing times tool for current estimates at your specific office.
USCIS issues a written denial explaining the reason. You may file a motion to reopen or reconsider, or appeal to the AAO on Form I-290B within 33 calendar days of the date shown on the mailed decision.
Yes. An SSN is required for US tax filing and financial reporting. Apply promptly after naturalization. An ITIN is not a substitute for a US citizen.
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