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N-400 naturalization applications

What the N-400 asks for, where firms lose time preparing it, what has changed in naturalization practice since 2025, and how Aion fills the form from the client's documents. Written for immigration attorneys, paralegals and DOJ-accredited representatives.

Last updated: 17 October 2026

The application at a glance

• The form: Form N-400, Application for Naturalization. The edition on the USCIS form page is dated 01/20/25. Check the edition date at the bottom of every page. A printed form with missing or mixed-edition pages can be rejected. It can be filed online through a USCIS account or on paper.
• General provision (5 years): the applicant is 18 or older and has been a lawful permanent resident for at least 5 years, with at least 5 years of continuous residence, at least 3 months in the state or USCIS district of filing, and physical presence of at least 30 months (913 days). Good moral character, attachment to the Constitution, English and civics, and willingness to take the Oath of Allegiance are also required (N-400 instructions).
• Marriage to a U.S. citizen (3 years): the applicant has been a permanent resident for at least 3 years, has lived in marital union with a spouse who has been a U.S. citizen for at least 3 years, and stays married to that spouse until the oath. Physical presence is at least half of the 3-year period.
• Early filing: generally up to 90 days before the required period of continuous residence is complete. The applicant must meet every other requirement at filing, and USCIS rejects applications filed too early. USCIS has an early filing calculator (Policy Manual, Vol. 12, Part D, Ch. 6).
• Absences: an absence of more than 6 months but less than 1 year is presumed to break continuous residence unless the applicant shows otherwise, for example by keeping a U.S. job, keeping access to a U.S. home, or leaving immediate family in the United States. An absence of 1 year or more breaks continuity unless the applicant has an approved Form N-470 for qualifying employment abroad. A reentry permit does not preserve continuous residence (Policy Manual, Vol. 12, Part D, Ch. 3).
• Good moral character: the applicant must show it for the statutory period (5 years, or 3 years on the marriage route) before filing and up to the oath.

The five-year history sections that cause most errors

USCIS uses Part 4 (residence), Part 7 (employment and schools) and Part 8 (time outside the United States) together to decide continuous residence, physical presence and the 3-month residency requirement. The three sections have to tell one consistent story. The look-back is 5 years on the general provision and 3 years on the marriage route.

Part 4: addresses

Every address in the look-back period, with dates. Gaps and overlaps in dates are easy to introduce when a client has moved several times.

Part 7: employment and schools

Every job and school, full time or part time, over the same period. The dates have to fit the address history and the tax records the client may bring to the interview.

Part 8: trips outside the United States

Every trip over the look-back period, most recent first, with the date left, the date returned and the countries visited. The form excludes day trips completed within 24 hours. For physical presence, USCIS counts both the day of departure and the day of return as days in the United States.

Part 8 is usually the slowest section to prepare. Clients forget short trips, entry and exit stamps are spread across old and new passports, and the totals have to support both the continuous residence and the physical presence rules. A trip of more than 6 months needs evidence of continued residence, such as tax transcripts, rent or mortgage statements, pay statements, bank statements, vehicle registration or passport stamps.

Parts 5 and 6: marital history and children

Marital history includes the applicant's spouse's earlier marriages, marriages abroad, and customary or religious marriages. The children section covers all children under 18, including stepchildren, adopted children, children living elsewhere and children born outside marriage. Willful failure to support dependents during the statutory period can defeat good moral character, so support evidence matters here.

Part 9: the conduct questions

The "EVER" questions reach conduct anywhere in the world at any time. The instructions say to report every offense, including those expunged, those that happened before age 18, and offenses involving solicitation, domestic violence or driving under the influence. An applicant who does not disclose an offense may be denied even if the offense itself would not have been disqualifying. Part 9 also asks about claims to U.S. citizenship, voting and voter registration, overdue taxes, and Selective Service registration.

What has changed since 2025

• Good moral character is assessed more broadly. A USCIS policy memorandum of August 15, 2025 (PM-602-0188) directs officers to a holistic, totality-of-the-circumstances review rather than a check for the absence of wrongdoing. It lists positive factors such as community involvement, family caregiving, education, stable lawful employment, length of residence and tax compliance. It also directs closer attention to conduct that may be lawful but contrary to community standards, such as reckless or habitual traffic infractions, and to evidence of rehabilitation such as paying overdue taxes or child support.
• Voting and false claims. USCIS revised its Policy Manual on August 29, 2025 on how unlawful voting, unlawful voter registration and false claims to U.S. citizenship bear on good moral character (policy alert). The N-400 asks about both in Part 9.
• Neighborhood investigations are back. USCIS resumed personal (neighborhood) investigations under INA 335(a) in August 2025, and a policy alert of August 25, 2026 (PA-2026-10) ended the general waiver. USCIS decides case by case whether to conduct or waive one. The alert says applicants may voluntarily provide testimonial or character reference letters, preferably from U.S. citizens who are not family members, and that USCIS considers them when deciding whether to waive an investigation. It also stresses that USCIS confirms what the applicant reports through documents, the investigation and interview testimony, so the N-400 needs to match the records.
• A new civics test. Applicants who file the N-400 on or after October 20, 2025 take the 2025 civics test. Earlier filers take the 2008 test (see below).
• Proposed fee changes. DHS published a proposed rule on June 23, 2026 that would change the fees for Forms N-400 and N-336 and the availability of fee waivers (Federal Register). It is a proposal. Check the USCIS Fee Schedule (G-1055) for the fee that applies on the filing date.

Evidence

Evidence goes in at filing, although USCIS may accept some at the interview. What a file needs depends on the basis and on the answers:

• Marriage route: proof the spouse has been a citizen for 3 years (birth certificate, certificate of naturalization or citizenship, Form FS-240 or the passport photo page), the current marriage certificate with any divorce, annulment or death records for earlier marriages, and evidence of 3 years in marital union such as joint accounts, leases, insurance and IRS transcripts.
• Trips over 6 months: evidence of continued residence, as listed above. The instructions suggest bringing IRS tax transcripts to the interview.
• Child and spousal support: court or agency orders and proof of payment, or a notarized letter from the parent or guardian caring for the children.
• Arrests and convictions: arrest reports, sentencing records, proof that probation or alternative sentencing was completed, or a statement that no charges were filed. Photocopies can go in with the application, and originals or court-certified copies come to the interview. Traffic incidents need documents only if they were alcohol or drug related, led to an arrest, or seriously injured someone.
• Overdue taxes: IRS transcripts, a signed repayment agreement and proof of its current status.
• Selective Service: a status information letter and a statement where registration was required and missed.
• Foreign-language documents: a full English translation with the translator's signed certification.

The interview and the civics test

The officer asks about the application and the client's background. Unless an exception applies, the client also takes an English test and a civics test (USCIS).

• English: speaking and understanding are assessed during the interview. The client reads one of three sentences aloud correctly and writes one of three sentences correctly.
• 2025 civics test (N-400 filed on or after October 20, 2025): 20 questions from a list of 128. The client passes with 12 correct answers and fails after 9 incorrect ones.
• 2008 civics test (N-400 filed before October 20, 2025): up to 10 questions from a list of 100. The client passes with 6 correct answers.
• Age and residence exception: applicants aged 65 or older who have been permanent residents for 20 or more years get 10 questions from a special bank of 20.
• Retesting: a client who fails a portion at the first interview is retested on that portion 60 to 90 days later.

Some answers change with elections and appointments, so check USCIS's test updates page before the interview.

Common mistakes

• Selecting more than one eligibility box in Part 1, or none. This can delay or reject the application.
• Filing more than 90 days before the continuous residence period is complete.
• Leaving out short trips, listing day trips, or reporting dates that do not match passport stamps.
• Address, employment and travel histories that contradict each other.
• Incomplete marital history or children lists, especially children who live elsewhere.
• Not disclosing an expunged, juvenile or old offense because the client thinks it does not count.
• Overdue taxes, or a past tax return filed as a nonresident alien, with no explanation or evidence.
• An unsigned form, a stamped or typed signature, or pages from different form editions.
• Preparing the client only for the civics test and not for the questions on character and conduct.

How Aion handles an N-400

1. Start an application in Aion, pick the N-400 (or several forms for the same client), and add your firm's attorney or preparer details once in the firm profile.
2. Upload the client's documents: green card, every passport, I-94 records, prior filings, tax transcripts, marriage and divorce records, court records, your intake questionnaire. Files, a folder or a .zip all work.
3. Aion extracts the identity, address, employment, marital, children and travel details into one summary and flags anything missing or contradictory. Travel history built from passport stamps and I-94 records is a typical source of gaps, and the summary shows them before anything is filled.
4. Your team reviews and edits the summary. The original documents are deleted as soon as extraction succeeds.
5. Aion fills the official, current-edition USCIS PDF field by field. Your attorney or preparer details are copied exactly from the firm profile, matching the G-28.
6. Flagged fields are outlined in red on the PDF and listed in the app with a note. You can type an answer or mark a field "correct as is" in the app and download a corrected PDF, or edit the PDF in Acrobat. Answers too long for a box can go on a downloadable addendum page.
7. Your attorney reviews the PDF, the client signs, and your firm files. Aion never signs or files, and never logs into a USCIS account.

What stays with your firm

• Advice on eligibility: absences, the continuous residence presumption, early filing and good moral character.
• Deciding what the client discloses and how, including old offenses and tax history.
• Whether to include character reference letters, preparing the client for the interview, signing, paying the fee and filing.

Related citizenship forms Aion supports

• N-336: request for a hearing on a decision in naturalization proceedings, after an N-400 denial.
• N-565: replacement of a naturalization certificate, certificate of citizenship, declaration of intention or repatriation certificate.
• N-600: application for a Certificate of Citizenship.
• N-600K: citizenship for a child who regularly lives outside the United States, through a U.S. citizen parent.

Worried about putting client data into an AI tool? Read Is it safe to use AI for US immigration forms? and our security summary. Comparing tools? See Aion vs Docketwise.

Sources: USCIS: Form N-400 · Instructions for Form N-400 (01/20/25) · Policy Manual, continuous residence · physical presence · jurisdiction and early filing · Policy Manual updates · The naturalization interview and test · Study for the test · N-336 · N-565 · N-600 · N-600K. This guide is general information, not legal advice. Requirements and fees change. Check USCIS before relying on any figure here.