N-400 Application Instructions: Complete Guide to Each Section

N-400 Application Instructions Overview

The N-400, Application for Naturalization, is the official USCIS form used to apply for U.S. citizenship. It's a detailed 18-page document organized into 20 numbered parts, each designed to gather specific information about your identity, residence history, travel history, employment, organizational memberships, and moral character. The instructions that come with the form run to 15+ pages on their own — USCIS publishes them separately at uscis.gov/n-400, and reading them thoroughly before you start filling out any part of the application is strongly recommended.

The purpose of the N-400 is to establish that you meet all requirements for naturalization: the required period of lawful permanent residence (typically 5 years, or 3 years if married to a U.S. citizen), continuous residence and physical presence in the U.S., good moral character, basic English language ability (unless exempt), and knowledge of U.S. civics. Every section of the form is designed to verify one or more of these requirements, and USCIS officers use the information you provide to prepare for your naturalization interview.

Accuracy and absolute completeness are critical throughout the entire form. USCIS systematically cross-references the information on your N-400 against immigration records, criminal databases, tax records, employment verification systems, and other government databases. Discrepancies between what you write on the form and what government records show can lead to a denial, a finding of misrepresentation, or in serious cases, criminal referral. The application for naturalization guide provides more detail on eligibility requirements if you're still determining whether you're ready to file. These instructions focus specifically on how to complete each part of the form correctly once you've confirmed your eligibility.

Parts 1–7: Your Personal Information and Residence History

Parts 1 and 2 of the N-400 establish your basic eligibility. Part 1 asks you to check the basis for your naturalization application: the standard 5-year LPR path, the 3-year path for those married to and living with a U.S. citizen, military service, or other qualifying basis.

Part 2 asks for your full legal name as it appears on your green card, as well as any other names you've ever used — maiden names, nicknames, name changes, and aliases. List every name you've used, even informally, even briefly. USCIS uses name variations to conduct background checks, and omitting a known alias can create a character issue at your interview.

Parts 3 and 4 collect your contact information and biographic data: current address, phone number, email, date and place of birth, nationality, race and ethnicity (for statistical purposes; this doesn't affect eligibility), height, weight, and eye color. These parts are relatively straightforward, but pay attention to how USCIS wants dates formatted — month/day/year (MM/DD/YYYY) consistently throughout the form.

Parts 5, 6, and 7 address your residence history, information for reentry, and time outside the United States. Part 5 requires you to list every address where you've lived for the last 5 years (or since becoming an LPR, if less than 5 years). Part 6 asks about your last entry to the U.S. — your date of entry, port of entry, and visa or travel document used.

Part 7 is one of the most detailed and error-prone sections: you must list every trip you've taken outside the United States during the last 5 years (or since becoming an LPR). For each trip, include the country visited, date of departure, date of return, and the number of days spent abroad. USCIS uses this to calculate your physical presence (required: 913 days in the past 5 years) and to verify continuous residence. The N-400 eligibility requirements page explains how extended absences affect your continuous residence and physical presence calculations if you're uncertain whether a particular trip creates an issue.

One practical tip for completing Part 7: don't rely solely on memory. Review your passport stamps page by page, check your email for flight confirmations and hotel receipts, look at your bank statements for foreign currency transactions, and review any social media posts or photos with location data from the 5-year period. Many applicants discover trips they had forgotten when they review their records systematically. Creating a spreadsheet with date of departure, date of return, destination, and days absent makes it easy to calculate your total days abroad and verify you meet the physical presence requirement before you file.

Parts 8–11: Employment, Organizations, and Good Moral Character

Parts 8 and 9 cover your employment and organizational memberships. Part 8 asks for your current employment and every employer during the last 5 years, including self-employment and periods of unemployment. List each employer's name, address, and your dates of employment. For periods of unemployment, note that you were not employed during that period — don't leave those years blank.

Part 9 asks whether you've been a member of, or associated with, any organization, club, society, group, or association, inside or outside the United States, at any time since becoming an LPR. This is a broad question: include professional associations, unions, religious organizations, civic groups, and cultural societies. The question is not asking only about problematic organizations — you must list all of them, including benign ones. Omitting a legitimate organization can look like concealment.

Part 10 focuses on continuous residence and physical presence again from a yes/no question format, and Part 11 is the most carefully reviewed section of the entire N-400 — the good moral character questions. Part 11 contains over 60 yes/no questions covering criminal history, immigration violations, and certain other conduct. These include questions about arrests, citations (including traffic violations that involved alcohol), court proceedings, probation, incarceration, failure to pay taxes, military service, polygamy, persecution of others, and extremist affiliations.

You must answer every question truthfully and completely. The instruction 'have you EVER' means in your entire lifetime — not just the last 5 years. If you have any criminal history at all, consult an immigration attorney before filing. The N-400 application page provides additional context on how criminal history affects naturalization eligibility.

When answering Part 11 questions, 'Yes' does not automatically mean you're ineligible. Many minor offenses, old convictions, and dismissed charges do not disqualify applicants. What matters is whether the offense is a disqualifying crime, when it occurred, and how it was resolved. What always disqualifies an applicant, however, is lying on the form — an omission or false answer to a Part 11 question about a criminal matter can result in permanent denial on misrepresentation grounds even if the underlying offense would have been forgiven.

Part 11 also includes important questions about tax filing obligations and past military service. The question about whether you've filed federal, state, and local income tax returns since becoming an LPR trips up some applicants who filed late, didn't file, or were unaware they owed taxes.

If you failed to file taxes in any year since becoming an LPR, address this with a tax professional before submitting your N-400 — IRS payment plans and late filings are generally viewed more favorably than undisclosed omissions. The question about military service applies to service in any country's military, not just the United States. If you served in a foreign military, you'll need to disclose it and may need to provide documentation.

Common N-400 Completion Mistakes and How to Avoid Them

The most frequently occurring mistake applicants make is incomplete travel history in Part 7. Many people forget short trips — a weekend visit to Canada or Mexico, a brief cruise that went into foreign waters, a one-week family visit. You need a record of every trip outside the U.S. during the 5-year period, no matter how short.

Pull your passport, check your travel records, review your bank statements for foreign transactions, and note any loyalty points credited to foreign flights. An incomplete travel list creates a discrepancy between your application and the government's entry/exit records, which USCIS will catch during the background check.

A second common error is not using the legal name that appears on your green card exactly as it appears. If your green card shows a middle name and you leave it out on the N-400, USCIS may flag the discrepancy. If your green card has a spelling error in your name, use the same spelling on the N-400 and note the discrepancy — bring documentation to explain it at your interview.

Similarly, failing to list name variations in Part 2 is a recurring issue: maiden names, names used in other countries, nicknames that appear on any official documents, and names from religious or cultural traditions all need to be disclosed.

Timing is a third major area of mistakes. You may file the N-400 up to 90 days before you reach your required residence period (5 years or 3 years, depending on eligibility basis), but not earlier. Filing too early leads to rejection or denial. Additionally, your continuous residence must remain unbroken from the date you file through the date of your naturalization ceremony — if you travel and incur a break after filing, it can affect your case. Checking the current N-400 processing time before you file helps you plan around anticipated interview and ceremony dates.

A fourth common mistake involves the filing fee. As of 2026, the mail filing fee is $760 and the online fee is $710, payable to the U.S. Department of Homeland Security. Checks or money orders made out to anything else — including USCIS or the U.S. Citizenship and Immigration Services — are rejected.

Also, make sure your check is for the correct amount: underpayment causes rejection; overpayment results in a refund delay. Fee waiver applications (Form I-912) must be submitted with the N-400 at the time of filing — you cannot add a fee waiver request after submission if your application was initially rejected for nonpayment.

Finally, many applicants fail to sign and date every page that requires a signature before mailing. The N-400 requires your signature in multiple places — Part 12 (attestation by interpreter if used), Part 13 (applicant's statement and signature), and Part 14 (applicant's certification). Missing any signature makes the application incomplete and subject to rejection. Review every page of your completed application before mailing or submitting online.

Parts 12–20: Oaths, Certification, and Final Submission

Parts 12 through 20 cover the applicant's and interpreter's certifications, the oath or affirmation requirements, information about disability accommodation requests, and the final signature and date. If you used an interpreter to help complete the form, Part 12 must be completed and signed by that interpreter. This doesn't mean the interpreter completed the form for you — it means you used someone to translate the questions from English for you. If you completed the form entirely in English without assistance, leave Part 12 blank.

Part 13 is your personal certification: you're declaring under penalty of perjury that everything on the form and in all accompanying documents is true and correct. Read this certification carefully before signing. Part 14 is reserved for the USCIS officer at your interview. Part 15 covers any requests for disability accommodations during the interview or naturalization ceremony. If you have a physical or mental disability that requires accommodations — such as a wheelchair-accessible interview location, a sign language interpreter, or extended time — check the applicable box and provide documentation with your application.

After completing the form, review every page once more before submitting. Many applicants find it genuinely helpful to have a trusted person — a family member, a community immigration advocate, or an experienced immigration attorney — review the completed N-400 carefully before filing to catch errors that are surprisingly easy to miss when you've been staring at the same form for extended hours.

Once submitted, USCIS will mail you a Receipt Notice (Form I-797) confirming that your application was received and is being processed. Keep this notice — you'll need it to check your case status online and to identify your case at your biometrics appointment and interview. The filing process overview covers what happens after submission, from biometrics through the oath ceremony.

After your application is accepted, USCIS will schedule a biometrics appointment at your local Application Support Center. You'll have your fingerprints, photograph, and signature taken for background check processing. Bring your appointment notice and a government-issued ID. The biometrics appointment is typically brief — 15–30 minutes — and you don't need an attorney present for it.

After biometrics, USCIS will complete the background investigation and schedule your naturalization interview, during which an officer will review your N-400 with you, test your English language ability (if not exempt), and administer the civics test (unless exempt due to age and disability). The civics questions you'll be tested on are drawn from the official USCIS list of 100 civics questions — you must answer at least 6 of 10 correctly to pass.

Preparing for this portion of the interview in advance is as important as filling out the form correctly. The civics study guide provides practice questions drawn from the official 100-question civics bank, organized by topic to help you study efficiently. Officers also have discretion to ask questions directly from your N-400 at the interview, so reviewing your completed application before the interview date is worthwhile — you should be able to confirm and explain any answer on the form without hesitation.