What Is the N-400 Form? A Plain-English Guide for New Applicants

You've been a permanent resident for years. You've built a life here. And somewhere along the way, you decided: it's time. Time to make it official, to become a citizen.

Then you go looking for where to start — and you find the N-400. A form. A long one. With sections about where you've lived, where you've worked, every country you've visited, and a list of yes-or-no questions that can feel intimidating even when you have nothing to hide.

Here's what you actually need to know.

What Is the N-400?

The N-400 is the Application for Naturalization — the official form you file with USCIS to begin the process of becoming a US citizen. It's not the interview. It's not the civics test. It's the paperwork that gets you there.

Filing the N-400 tells USCIS: I believe I'm eligible for naturalization. Here is my history. Please review it.

USCIS then processes your application, schedules a biometrics appointment (fingerprints and photo), and eventually invites you to a naturalization interview — where an officer reviews your form with you, tests your English, and administers the civics test. If you filed on or after October 20, 2025, that means 20 questions from the official list of 128, with 12 correct needed to pass. Pass that, and you're on your way to the oath ceremony.

Who Can File the N-400?

According to the official N-400 instructions, you generally need to meet all of the following to be eligible:

• Age 18 or older at the time you file
• Lawful permanent resident for at least 5 years — or 3 years if you've been married to and living with a US citizen for that full period
• Continuous residence: you've maintained continuous residence in the US for at least 5 years (or 3 years for the spouse rule)
• 3-month district residency: you've lived in the USCIS district or US state where you're filing for at least 3 months
• Physical presence: you've been physically in the US for at least 30 months (913 days) of the last 5 years — or 18 months of the last 3 years for the spouse rule
• Good moral character: demonstrated good moral character during the required period
• Attachment to the Constitution: you support the principles of the US Constitution
• English and civics: able to read, write, speak, and understand basic English, and demonstrate knowledge of US history and government
• Willing to take the Oath of Allegiance

Not sure if you qualify? USCIS offers a Naturalization Eligibility Tool that walks you through the requirements.

USCIS allows you to file the N-400 up to 90 days before you hit your residency milestone. So if you'll hit your 5-year mark in October, you can file as early as July.

What Does the N-400 Actually Ask?

The form has 16 parts. Most of it is straightforward — your name, address, Social Security number, employment and school history for the last 5 years, your marital history, your children, and a record of every trip you've taken outside the US. Tedious, but not complicated.

The part that makes people nervous is Part 9: Additional Information About You, which covers Good Moral Character. It's a long list of yes/no questions covering things like:

• Have you ever been arrested, cited, or detained?
• Have you ever failed to file a federal tax return?
• Have you ever claimed to be a US citizen?
• Have you ever been a member of a terrorist organization?
• Have you ever participated in persecution of any person?

These questions sound alarming in print. They're not designed to trick you — they're designed to surface facts that could disqualify an applicant or that USCIS already knows about and wants to confirm. Answer honestly. If you have a complicated history, this is exactly why you should talk to an immigration attorney before filing.

For the vast majority of applicants, every answer in Part 9 is "No" — and the form goes smoothly.

How to File the N-400

You have two options: file online through your myUSCIS account at uscis.gov, or mail a paper form. Online filing is generally easier — it walks you through each section, lets you save progress, and confirms receipt instantly. Paper is also valid if you prefer it.

When you file, you'll also submit:

• A copy of your green card (front and back)
• The filing fee (check uscis.gov/n-400 for the current amount — fees are listed on Form G-1055 and can change)
• Any supporting documents for items you disclose in the application (e.g., court records, tax transcripts if you have overdue taxes, marriage certificate if filing as a spouse of a US citizen)

Note: passport-style photos are only required for applicants filing from outside the United States. Most domestic applicants do not submit photos with the N-400.

What Happens After You File?

Once USCIS receives your application, the waiting begins. Here's the typical sequence:

1. Receipt notice — arrives within a few weeks, confirms your case number
2. Biometrics appointment — you go to an Application Support Center to have your fingerprints taken
3. Interview notice — when your case is ready, USCIS sends a notice with your interview date, time, and what to bring
4. Naturalization interview — the officer reviews your form, tests your English, and asks civics questions; see our full guide on what to expect at your naturalization interview
5. Decision — granted, continued (needs more information), or denied
6. Oath ceremony — you take the Oath of Allegiance and officially become a citizen

Processing times vary dramatically by field office and current USCIS backlogs. Some applicants wait 8 months. Others have waited over 2 years. You can check current processing times by field office at egov.uscis.gov/processing-times.

The Civics Test: What to Start Doing Right Now

Here's the thing most applicants underestimate: the civics test isn't something you cram for the week before your interview. It works better when you practice the actual format — an officer asks you a question out loud, and you answer out loud, just like a conversation.

If you filed your N-400 on or after October 20, 2025, you'll take the 2025 civics test: the officer asks 20 questions from the official list of 128, and you need to answer 12 correctly to pass. If you filed before that date, you're on the older test — 10 questions, 6 correct to pass. Either way, the questions cover US history, government structure, and rights and responsibilities. Some are easy. Some are genuinely tricky if you haven't practiced them recently.

Read our guide on how to answer civics questions out loud — it covers the verbal practice techniques that actually work, including how to handle questions you blank on mid-answer.

And if you're worried about what happens if you don't pass the civics portion at your interview, we've got that covered too: what happens if you fail the civics test.

One Last Thing Before You File

The N-400 is a long form, but it isn't complicated for most applicants. Read every question. Answer honestly. Double-check your travel history — especially if you travel frequently for work. If anything in Part 9 gives you pause, a 30-minute consultation with an immigration attorney is worth every penny before you submit.

The form is the beginning. The interview is where it gets real. Start practicing the civics questions now — not the week your interview notice arrives.