US Immigration Form
Form N-400 — Application for Naturalization
Form N-400 is the application a lawful permanent resident files to become a naturalized US citizen. Naturalization is the legal process by which a noncitizen voluntarily becomes a citizen of the United States. It is the final step in the immigration journey for most permanent residents, and it confers the full rights and responsibilities of US citizenship, including the right to vote, the right to run for most public offices, the ability to sponsor a wider range of family members for immigration, and protection from deportation.
To qualify for naturalization, you must meet several statutory requirements established by Congress. You must have been a lawful permanent resident for a specific period — generally five years, or three years if you are married to a US citizen. You must demonstrate continuous residence and physical presence in the United States. You must be a person of good moral character. You must demonstrate an attachment to the principles of the US Constitution. And you must pass an English test and a civics test covering US history and government.
The N-400 is a detailed application that asks about your residence history, employment history, marital history, children, travel outside the United States, criminal history, and affiliation with organizations. USCIS reviews every answer carefully, and discrepancies between the N-400 and prior immigration filings can raise concerns. This guide explains what Form N-400 is, who qualifies, what the process involves, and the most common mistakes applicants make.
Who files this form
Form N-400 is filed by lawful permanent residents who meet the statutory requirements for naturalization. The general requirement is five years of permanent residence, but the period is reduced to three years if you have been married to and living with a US citizen spouse for those three years. Certain military service members and their families may qualify under special provisions with reduced or no residence requirements.
To be eligible, you must also demonstrate continuous residence in the United States, meaning you have not taken trips abroad that are so long they break the continuity of your residence. You must meet the physical presence requirement — at least half of the required residence period physically in the United States. You must have lived in the state or USCIS district where you file for at least three months. And you must be a person of good moral character during the statutory period leading up to your application.
What this form is for
The purpose of Form N-400 is to allow USCIS to evaluate whether a lawful permanent resident meets all the statutory requirements for naturalization. USCIS reviews the application for completeness, consistency with prior immigration records, and any grounds that might disqualify the applicant. The review includes a background check, a biometrics appointment, and an in-person interview where the applicant is tested on English and civics.
If USCIS approves the application, the applicant is scheduled for a naturalization ceremony where they take the Oath of Allegiance to the United States. After taking the oath, they receive a Certificate of Naturalization and are immediately a US citizen. The process typically takes several months from filing to oath, but the timeline varies by USCIS field office and case complexity. Check the current USCIS processing times for the most accurate estimate.
Key sections
- Part 1 — Information about your eligibility: the basis for your naturalization application
- Part 2 — Information about you: name, A-number, date and place of birth, and social security number
- Part 3 — Residence and physical presence: address history and trips outside the United States
- Part 4 — Information about your parents and marital history
- Part 5 — Information about your children and employment history
- Part 6 — Moral character and criminal history: arrests, convictions, and affiliations
Common mistakes
- Filing before meeting the full residence or physical presence requirement
- Not disclosing a prior arrest or citation, even if the case was dismissed or expunged
- Failing to account for all trips outside the United States, including short weekend trips to Canada or Mexico
- Not updating USCIS after moving to a new address — the interview notice will be sent to your address on file
- Studying the wrong civics questions — the test draws from a specific list of 100 questions published by USCIS
- Paying the wrong filing fee — check the current USCIS fee schedule for Form N-400 before submitting
Official sources
Always verify the current form edition, fee, and instructions on the government site before filing. This guide is educational and not a substitute for your DSO or a licensed attorney.
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Frequently asked questions
- How long do I need to live in the US before applying for citizenship?
- Most permanent residents must wait five years after receiving their green card before applying for naturalization. If you are married to a US citizen and have been living with them for three years, you may apply after three years. Certain military service members may qualify with shorter or no residence requirements.
- What is the English and civics test?
- During your naturalization interview, a USCIS officer will test your ability to read, write, and speak basic English. You will also be asked up to 10 questions from a list of 100 civics questions about US history and government. You must answer at least 6 of the 10 questions correctly to pass. USCIS publishes the full list of 100 questions and answers on its website.
- Can I apply for naturalization if I have a criminal record?
- It depends on the type of conviction and when it occurred. Certain crimes permanently bar naturalization, while others create a temporary bar during a specific period. Even dismissed charges or expunged records must be disclosed on the N-400. USCIS will review your complete criminal history during the background check. Consult an immigration attorney if you have any criminal record before filing.
- Does time outside the US affect my eligibility?
- Yes. An absence of more than six months but less than a year creates a rebuttable presumption that you broke continuous residence — you can overcome it with evidence of ongoing ties (a home, a job, family, tax filing). An absence of one year or more breaks continuous residence. A re-entry permit preserves your green-card status so you can re-enter, but it does NOT preserve continuous residence for naturalization — that requires Form N-470, available only in limited situations such as qualifying employment abroad. You must also meet the physical presence requirement. Keep records of all your trips.
- What happens at the naturalization ceremony?
- After your N-400 is approved, USCIS will schedule you for a naturalization ceremony where you will take the Oath of Allegiance. The ceremony is typically held at a courthouse or USCIS office. You will return your permanent resident card, take the oath, and receive a Certificate of Naturalization. You are a US citizen from the moment you take the oath.