Form N-400, Application for Naturalization, is the official USCIS form used by lawful permanent residents (LPRs) and other eligible individuals to apply for US citizenship. Completing the form accurately and completely is one of the most critical steps in the naturalization process — errors, omissions, or inconsistencies in the N-400 are among the most common reasons applications are delayed, requests for evidence (RFEs) are issued, or applications are denied. USCIS officers review every response on the form in detail during your naturalization interview, often asking you to confirm or elaborate on specific answers you provided.
The current version of Form N-400 is available only on the USCIS website at uscis.gov. You should always download the most current version before completing the form, as USCIS updates forms periodically and using an outdated version can result in rejection. The official USCIS N-400 instructions document is a detailed companion to the form itself and runs approximately 20 pages — reading it fully before starting the form will prevent many of the mistakes applicants make when completing the form based on guesswork alone. You can access these instructions directly from N-400 form instructions resources and the USCIS website.
Most applicants file Form N-400 online through the USCIS online account system, which allows you to save your progress and edit responses before submission. Online filing also speeds up receipt notice generation and allows for more efficient case status tracking. Paper filing by mail is also accepted, though processing times for mailed applications can be longer than online submissions in some USCIS field offices. All filers pay the same base fee of $760 (as of 2025), with a biometric services fee included for most applicants.
Form N-400 has 18 numbered parts that collect information about your identity, marital history, residence and employment history, time outside the United States, organizational affiliations, and legal and moral history. The form also includes a significant section of 'yes or no' questions covering everything from prior criminal history to past claims of US citizenship. Many of these questions are counterintuitive — the word 'ever' appears frequently, and applicants must answer based on their complete lifetime history, not just recent years.
Working through the N-400 carefully, section by section, is the best approach. Rushing through the form to submit quickly leads to errors that create complications during the interview. This guide walks you through each major section of Form N-400 with explanations of what information is required, what common mistakes to avoid, and what documentation to have ready for supporting the responses you provide.
Name, eligibility basis (LPR for 5 years, marriage to USC, military, etc.), personal information, and any requested disability accommodations.
Contact information, work history, marital history, children, residence history for the past 5 years, and employment history.
All trips outside the US in the last 5 years, continuous residence determination, and physical presence calculation.
Good moral character questions covering criminal history, tax compliance, registration requirements, and willingness to take the Oath of Allegiance.
Part 1 collects your full legal name as it appears on your Green Card and asks for any other names you have used, including maiden names, name changes, and aliases. It's critical that your name on the N-400 matches exactly how it appears on your Permanent Resident Card (Form I-551). If there is a discrepancy due to a name change or translation issue, note this in the comments section rather than entering a different name — inconsistencies between your ID documents and the form prompt questions during the interview.
Part 2 establishes your basis of eligibility for naturalization. Most applicants qualify as LPRs for 5 years continuously, but other eligibility categories exist including the 3-year rule for spouses of US citizens, veterans who served honorably during specified periods, and special provisions for employees of certain US companies. Selecting the wrong eligibility category can result in denial, so verify your eligibility before completing the form. The USCIS Naturalization Eligibility Quiz at uscis.gov is a useful tool for confirming which category applies to you.
Parts 3 through 5 collect personal information including your Social Security number, date and country of birth, physical description, current mailing address, and daytime phone number. These sections are straightforward but require care with dates — USCIS uses MM/DD/YYYY format consistently throughout the form. Incorrect date formatting causes processing delays when data entry staff cannot reconcile conflicting date fields. Your USCIS Alien Registration Number (A-Number) from your Green Card must be entered correctly — a transposed digit can link your application to the wrong record.
Part 6 asks for your complete marital history. You must list every marriage you have ever had, including prior marriages that ended in divorce, annulment, or the death of a spouse. Provide the full name of each spouse, the date and place of marriage, and how the marriage ended with the date it ended.
Failing to disclose a prior marriage when it later appears in a background check is considered misrepresentation and can have severe consequences, up to and including denial and deportation proceedings. If you are currently married to a US citizen and using the 3-year rule, your marriage must still be legally valid at the time of filing and at the naturalization interview.
Parts 7 and 8 request information about your children (biological, adopted, and stepchildren, regardless of their citizenship or where they live) and your residence and employment history for the past 5 years. List every address where you have lived for the past 5 years in reverse chronological order, starting with your current address. For employment history, list every employer, self-employment, and period of unemployment.
Gaps in employment history require an explanation — 'unemployed' with dates is an acceptable entry. These sections establish the factual foundation that supports your claim of continuous residence and good moral character. You can review N-400 processing time information to plan the timeline from filing to interview.
Part 9 is one of the sections applicants most frequently complete incorrectly. It requires you to list every trip you have taken outside the United States during the past 5 years (or 3 years if applying under the marriage rule), including the destination country, date of departure, date of return, and total number of days outside the US for each trip.
You must list trips even if they lasted only one day. The total days outside the US calculated from Part 9 is used to verify that you meet the physical presence requirement — at least 30 months of physical presence in the US during the 5-year period (or 18 months in 3 years for the marriage rule).
Parts 10 and 11 address organizational memberships, foreign military service, and continuous residence. You must list every organization, association, club, fund, foundation, or similar group you have been a member of or associated with since your 18th birthday — including school clubs, religious organizations, labor unions, and community associations.
The continuous residence questions ask whether you have ever claimed to be a non-resident for tax purposes, failed to file income taxes, or had any breaks in continuous residence. If you filed as a non-resident alien on any US tax return, this must be addressed with documentation before your application will be approved.
Part 12 is the longest section of Form N-400 and the one applicants find most intimidating. It contains approximately 40 yes/no questions covering arrests, citations, crimes, traffic violations, drug use, gambling, failure to pay taxes, failure to register with the Selective Service, claims to be a US citizen, and many other topics.
The key rule for this entire section is to answer based on your complete lifetime history worldwide, not just within the US. A crime committed in another country must be disclosed. An arrest that was expunged or dismissed must be disclosed — the form asks whether you were 'ever' arrested, not whether you were convicted or whether the record still exists.
Answering 'yes' to a Part 12 question does not automatically disqualify you from citizenship. Many crimes and arrests are reviewed under the 'good moral character' standard, which has specific legal definitions and time thresholds. Certain crimes are 'bars' to naturalization if committed within a statutory period, while others are reviewable.
If you have any criminal history, consult with an immigration attorney before filing Form N-400 — the stakes of an incorrect disclosure or a misunderstood bar to naturalization are too high to navigate without professional guidance. Never answer 'no' to a Part 12 question when the truthful answer is 'yes' — officers compare your N-400 to FBI records, and misrepresentation is grounds for permanent bar from naturalization.
Parts 13 and 14 cover the Oath of Allegiance requirements. You must affirm that you are willing to bear arms for the US, perform noncombatant service, and perform work of national importance under civilian direction when required by law. There are accommodation processes for religious conscientious objectors that allow modified oath language. Part 14 is your signature certifying that all information provided is true and correct. Sign in the presence of the USCIS officer at your biometrics appointment or the officer at your interview — not in advance at home for a paper filing — to avoid signature complications.
Form N-400 must be submitted with a specific set of supporting documents, and the required documents vary depending on your eligibility category and the specifics of your application. For the standard 5-year LPR category, the basic document requirements include a copy of your Permanent Resident Card (front and back), any legal name change documents, and marriage certificates or divorce decrees if applicable to your eligibility basis. Do not send original documents — send clear photocopies of all supporting documents unless the instructions specifically require originals.
Your filing package must also include the correct fee payment. As of 2025, the N-400 base fee is $760 for most applicants, which includes the biometric services fee. USCIS accepts online payment, credit/debit card, checks, and money orders. Fee waivers are available for applicants who meet income guidelines and submit Form I-912 (Request for Fee Waiver). Reduced fees are available for certain qualifying low-income applicants who do not meet the full waiver criteria. The fee and any approved waiver or reduction must be clearly documented in your filing package.
If you have any criminal or immigration history that requires additional documentation — police clearance letters, court disposition records, certified copies of convictions, or immigration court records — include certified copies of these documents with your initial filing rather than waiting for USCIS to issue an RFE requesting them. Proactive inclusion of relevant records demonstrates good faith and often prevents delays in the adjudication process. Your attorney or accredited representative can advise on exactly what documentation is required for any specific type of criminal or immigration history.
After USCIS receives your complete filing package, you'll receive a receipt notice (Form I-797) within a few weeks. This notice contains your receipt number, which you can use to track your case status online at uscis.gov/casestatus. Your biometric services appointment will be scheduled next, where your fingerprints and photograph are taken. After biometrics, your case enters interview scheduling, which varies significantly by field office and can range from a few months to over a year in high-caseload offices. The N-400 filing fee guide provides complete 2025 fee information including waiver eligibility.
The USCIS naturalization interview is not a separate process from your Form N-400 — it's a direct review of everything you submitted. Your interviewing officer will have your N-400 in front of them and will go through the form section by section, asking you to confirm, correct, or elaborate on your responses. This is why accuracy and completeness on the form matters so much: the interview is essentially an oral review of what you wrote, under oath.
Officers frequently ask applicants to confirm their marital history, travel history, and organizational memberships in detail. If you listed a trip to Canada that lasted three days and it actually lasted four, the officer will notice if your verbal answer doesn't match. Bring your passport(s) to the interview — officers commonly ask to see entry and exit stamps to verify travel history responses. If there are any discrepancies between your stamps and your N-400 travel list, be prepared to explain them calmly and provide a corrected list if necessary.
The civics and English language portions of the naturalization interview are administered separately from the N-400 review. During the English test, the officer evaluates whether you can read, write, and speak basic English — they'll ask you to read a sentence, write a sentence they dictate, and converse naturally throughout the interview. For the civics test, the officer asks up to 10 of the 100 USCIS civics questions, and you must answer at least 6 correctly. Both the civics and English portions have age and long-term residency exemptions for certain applicants.
After a successful interview, most applicants receive an approval notice at the end of the appointment or by mail shortly after. You'll then be scheduled for the Oath of Allegiance ceremony, which formally confers citizenship. For applicants who have issues arise at the interview — outstanding criminal history questions, travel that may have disrupted continuous residence, or documents that need follow-up — the officer may continue the case or issue an RFE before making a final decision. Understanding the full process from application through oath helps you prepare at every stage and reduces anxiety on interview day.