Form N-400 is the official Application for Naturalization, the document you submit to USCIS when you're ready to apply for U.S. citizenship. It covers your personal history, residence and employment history, travel history, and eligibility basis for naturalization. USCIS uses the form to assess whether you meet the legal requirements for citizenship, including continuous residence, physical presence, good moral character, and attachment to the principles of the U.S. Constitution. Submitting the N-400 initiates a multi-step process that ends with an oath of allegiance and the issuance of a Certificate of Naturalization.
Naturalization through the N-400 process is available to lawful permanent residents (green card holders) who meet specific eligibility criteria. The most common path is the five-year continuous residence requirement: you must have been a lawful permanent resident for at least five years, been physically present in the United States for at least 30 months during that five-year period, and not had any single trip outside the US of six months or longer.
Marriage to a U.S. citizen provides a shorter three-year path if you've been married to and living with the same U.S. citizen for the full three years prior to filing and have been a lawful permanent resident for those same three years.
The uscis naturalization process is comprehensive and can feel overwhelming when you look at the form in its entirety. Form N-400 has 18 parts, with questions covering your background, residence and employment history, time outside the US, marital history, children, affiliations (organizations you belong to), criminal history, and your commitment to the U.S. Constitution.
While the form is long, most of the questions are straightforward to answer if you have your records organized in advance. The key is gathering the right documentation before you start, taking your time with the questions, and being completely accurate — USCIS will cross-reference your answers with existing records, and inconsistencies can create significant delays or problems.
Before filing Form N-400, confirm you meet all of the following requirements. Filing prematurely — before you have met the required residence or physical presence period — will result in denial and loss of the filing fee. USCIS begins counting your eligibility period from the date you were admitted as a lawful permanent resident, not from the date you entered the US on any prior visa.
Continuous Residence (5-Year Path): You must have been a lawful permanent resident for at least five years immediately preceding the date you file your N-400. Continuous residence means you haven't broken your residence — typically, a single trip outside the US of six months or more (but less than one year) creates a presumption that continuous residence was broken.
If you had such a trip, you may need to provide evidence that you maintained ties to the US (employment, property, family) throughout the absence. Trips of one year or more usually break continuous residence entirely unless a special permit was obtained before leaving.
Physical Presence (5-Year Path): In addition to continuous residence, you must have been physically present in the US for at least 30 months out of the five years immediately preceding filing. Count each calendar day you spent in the US during the five-year period. Even if your trips abroad were each individually less than six months, your cumulative time abroad cannot exceed 30 months in the five-year period or you won't meet the physical presence requirement.
State and District Residence (90-Day Rule): You must have lived in the state or USCIS district where you're applying for at least three months immediately before filing. This affects which USCIS field office will handle your application and conduct your interview. If you recently moved, you may need to wait three months or file in your prior location, depending on timing.
Good Moral Character: You must demonstrate good moral character for the statutory period (five or three years preceding filing, through the oath ceremony). USCIS reviews criminal history, tax compliance, child support obligations, polygamy, fraud in prior immigration filings, and other factors. Certain criminal convictions are permanent bars to naturalization; others require a period of rehabilitation. If you have any criminal history — even minor citations or arrests that didn't result in conviction — disclose them fully. Application fees are non-refundable even if denied, so ensuring you meet all requirements before filing protects your investment.
English and Civics: Unless you qualify for an exemption, you must demonstrate English language ability (reading, writing, and speaking) and knowledge of U.S. history and government (the civics test). Exemptions exist for applicants who are 50+ years old and have been a permanent resident for 20+ years (the 50/20 exemption), 55+ years old and a permanent resident for 15+ years (the 55/15 exemption), or applicants with qualifying disabilities (who may request a medical certification for an exemption using Form N-648).
Who qualifies: Most permanent residents who received their green card through employment, family (other than marriage to a U.S. citizen), or other means.
Residence requirement: 5 years of continuous lawful permanent residence immediately before filing.
Physical presence: 30 months (out of 60) physically present in the US.
State/district: 3 months of residence in the state/district before filing.
Good moral character: 5-year lookback period.
Who qualifies: Applicants who have been married to and living with the same U.S. citizen for the entire 3 years before filing, and who have been a lawful permanent resident for those same 3 years.
Residence requirement: 3 years of continuous lawful permanent residence.
Physical presence: 18 months (out of 36) physically present in the US.
Note: If your U.S. citizen spouse dies before you file, you may still qualify under certain conditions. Consult an immigration attorney if this applies to you.
Military service (INA §328/329): Active-duty service members and honorably discharged veterans may have different or reduced residence and physical presence requirements. Some may be able to apply immediately without the standard waiting period during periods of declared hostility.
Overseas employees (INA §319(b)): Spouses of U.S. citizens employed abroad by qualifying organizations may apply without meeting the standard residence requirements.
Adopted children and other categories: Multiple special categories exist. If you're unsure which section applies to your situation, review USCIS's eligibility guide or consult an immigration attorney.
Gathering all required documents before you start completing the form is strongly recommended. Having your documents organized prevents errors, ensures your form answers are accurate, and allows you to verify eligibility before investing time and money in the application. The specific documents you need depend on your eligibility path, but the core list applies to all applicants.
All applicants must provide: a copy of your Permanent Resident Card (front and back), two passport-style photographs (2 inches × 2 inches, white background), a copy of all passport pages showing entry and exit stamps for all international travel, and federal tax returns for the applicable statutory period (five years for the standard path, three years for the marriage path). If you've changed your name since receiving your green card, include name change documentation (court order, marriage certificate, or divorce decree).
Marriage-based applicants (three-year path) must additionally provide: the marriage certificate, proof of your spouse's U.S. citizenship (U.S. passport or Certificate of Naturalization), documentation of joint residence (lease agreements, mortgage documents, or shared utility bills), and joint financial documentation (joint tax returns, joint bank account statements, or insurance policies listing both spouses). USCIS requires evidence that the marriage is genuine and ongoing, not just a paper record of the ceremony.
If you have any arrests, citations, or criminal charges in your history — regardless of whether they resulted in conviction, were dismissed, or were expunged — you must disclose them and provide certified court dispositions. USCIS has access to criminal records databases and will identify undisclosed arrests. Proactive disclosure with supporting documentation demonstrating resolution of the matter is far better than a discovered omission. For a complete overview of what happens after you submit your documents, the u.s. citizenship instructions page provides additional guidance on the post-submission process and interview preparation.
If you are applying through the military path, you will also need a completed Form N-426, Request for Certification of Military or Naval Service. Spouses applying under the three-year marriage rule should gather joint tax returns, lease agreements, and bank statements showing commingled finances to demonstrate a bona fide marriage. All foreign-language documents must be accompanied by a certified English translation — the translator must certify their competence and the accuracy of the translation. USCIS does not accept notarized translations alone; the translator must sign a certification statement.
Make photocopies of every document you submit. USCIS retains originals in some cases, and having copies ensures you can reconstruct your package if documents are lost in transit. Keep the originals of vital documents — passports, birth certificates, and naturalization certificates — in a secure location. Use a sturdy mailing envelope and consider adding a cover letter to organize your package, especially if you are submitting multiple supporting attachments.
The most important instruction for completing Form N-400 is: answer every question honestly and completely. USCIS has access to extensive federal, state, and local databases, and inconsistencies between your form answers and existing government records are one of the most common causes of delays, requests for evidence, and denials. Even if you believe a prior issue is resolved, sealed, or expunged, answer the applicable question YES if it occurred during the statutory period and provide the supporting documentation. USCIS officers are trained to verify answers and will note any discrepancy between your form and their records.
For the travel history section (Part 6), document every trip outside the United States during the applicable statutory period. Review your passport and any prior travel documents for all entry and exit stamps. If you used multiple passports (due to renewal), gather all of them for reference.
If you are missing records of specific trips, try to reconstruct them from credit card statements, airline booking confirmations, or family records. Providing complete, accurate travel history is critical for the physical presence calculation that determines your eligibility. The cover letter that accompanies your application package can note if any travel records require explanation.
For the questions about affiliations (Part 10), list all organizations, clubs, associations, and groups you have been a member of or associated with since age 18, anywhere in the world. This includes professional associations, labor unions, religious organizations, cultural groups, and political parties. The questions about certain specific affiliations (terrorist organizations, Nazi parties, Communist parties) are serious legal questions — answer them carefully and truthfully. Most applicants answer NO to these questions because the vast majority of organizations people belong to are ordinary civic, professional, and social groups.
Review the completed form carefully before signing and submitting. The Part 17 attestation is a legal certification that all information is true and accurate — signing with false information is a federal offense. If you realize after signing that an answer is incorrect, complete a new form rather than crossing out or correcting an already-signed form. Once submitted, you cannot revise your form — any corrections become part of your record at the interview when the officer reviews your form with you and gives you an opportunity to clarify or amend answers under oath.
You can file Form N-400 either online through the myUSCIS portal or by mail to a USCIS lockbox facility. Online filing is generally faster, provides immediate confirmation of receipt, and gives you a case tracking number to monitor your application status through your myUSCIS account. Mail filing is an option for those who prefer paper forms or cannot easily use the online system, but requires a certified mailing receipt to confirm delivery.
For online filing, create an account at my.uscis.gov, select Form N-400, complete the form digitally, upload required supporting documents as PDF files, and pay the filing fee by credit or debit card. Your application is immediately date-stamped upon submission.
For mail filing, download the current version of Form N-400 from USCIS.gov (not from a third-party website — use only the official USCIS form), complete it in black ink, assemble your documents, and mail the complete package via USPS with Certified Mail and Return Receipt to the USCIS lockbox address for your state. The correct mailing address varies by state and by whether you're requesting a fee waiver — check USCIS.gov for the current address before mailing.
After filing, you'll receive a receipt notice (Form I-797C) confirming USCIS has received your application and providing your receipt number. Your first next step is a biometrics appointment, where USCIS collects fingerprints and a photo for background check purposes. The background check covers FBI criminal records and other federal databases. After the background check is complete, USCIS will schedule your naturalization interview. The timeline for each step varies by field office and application volume — monitoring the current N-400 processing time for your USCIS office helps you set realistic expectations for how long each stage will take.
After filing, your case moves through a sequence of steps before you receive your Certificate of Naturalization. Understanding the typical sequence helps you prepare for each milestone and avoid unnecessary anxiety about the process.
The biometrics appointment occurs first — typically 4–8 weeks after receiving your receipt notice. You'll go to a USCIS Application Support Center (ASC), have your fingerprints taken, and have a photograph taken. Bring your biometrics appointment notice and a valid photo ID. The biometrics are used for the criminal background check; if the check is clean, your case moves forward. If a background check issue arises, USCIS may request additional documentation or explanation before scheduling your interview.
The naturalization interview is the central evaluation event. A USCIS officer reviews your N-400 with you, asks you to confirm or correct your answers, evaluates your English language ability through the interview conversation itself, and administers the civics test. For the N-400 civics test, you'll be asked up to 10 questions from the official 100-question civics test, and you must answer at least 6 correctly.
The officer will also review your supporting documents and may request originals of documents you submitted as copies. Preparing thoroughly for the civics test in advance of your interview is essential — the test is administered orally, and you must answer from memory, not from notes.
After a successful interview, USCIS will either approve your application immediately or send a written notice of approval by mail. You'll then be scheduled for an oath ceremony, where you take the Oath of Allegiance and receive your Certificate of Naturalization. The ceremony may be a USCIS administrative ceremony (scheduled by USCIS) or a judicial ceremony (held in a court). Upon completing the oath, you are a U.S. citizen and eligible to apply for a U.S. passport. The entire process from filing to oath typically takes 8–24 months depending on your USCIS field office and current application volumes.