The N-400 is a 21-page form — longer than most government forms you've encountered, and more detailed than most people expect. Before you sit down to fill it out, it helps to know what you're walking into. This section-by-section walkthrough gives you a preview of every major part of the form so you don't run into surprises mid-application.
The official N-400 form is available as a free download from the USCIS website at uscis.gov/n-400. The current edition number and expiration date appear in the top right corner of the form — always make sure you're using the most current version. USCIS changes forms periodically, and submitting an outdated version can result in rejection.
This section asks you to identify which eligibility basis you're applying under. You check a box indicating whether you're applying under the 5-year lawful permanent resident path, the 3-year path (if married to a U.S. citizen), a military service path, or another basis.
This seems simple, but errors here cause real problems. If you check the wrong box — say, you check the 3-year path because you're married to a U.S. citizen but you've only been a permanent resident for 2 years — USCIS will deny your application for insufficient continuous residence. Double-check your eligibility before you select anything.
Your legal name, any other names you've used, your current address, and contact information. If your name has changed since you became a permanent resident (through marriage, divorce, or court order), list both the name on your green card and your current legal name. USCIS will process your citizenship under the name on file, and you'll need to have changed it legally before citizenship if you want the change reflected on your Certificate of Naturalization.
Gender, ethnicity, race, height, weight, and eye color. This section is used for identification and biometric matching purposes. It's straightforward — just answer accurately.
Your address history for the past 5 years and your employment or school history for the past 5 years. This is where organization helps. Before you start the form, create a list of every address where you've lived and every employer or school you've attended in the past 5 years, with start and end dates. Gaps in history raise questions — if you moved between residences within a week, include both. If you were unemployed for a period, there's a field for that.
Don't round dates. If you started a job on March 14, 2022, write March 14, 2022. USCIS checks these against employment records and tax filings.
Your Social Security number and driver's license or state ID information. This allows USCIS to run the background check that's part of every naturalization application. Make sure the information matches exactly what's on your identification documents.
You confirm you've lived in the U.S. continuously since becoming a permanent resident. You specify whether you've ever filed to be classified as a nonresident alien for tax purposes — this matters because doing so can break your continuous residence for naturalization purposes.
If you answered yes to any of these tax-related questions, consult an immigration attorney before filing. What seems like an old tax filing decision can have significant naturalization implications.
This is often the most labor-intensive section to complete. You must list every trip outside the U.S. lasting 24 hours or more during the 5 years before your application date. For each trip you list the destination country, the departure date, and the return date.
USCIS verifies this section against CBP travel records. If your list is incomplete — even by one brief trip you forgot about — it can create a discrepancy that triggers additional scrutiny. Pull your passport and go page by page through your stamps. Check your bank and credit card records for foreign transactions that might reveal trips you forgot.
If you've been absent from the U.S. for more than 6 months on a single trip, or more than a year in total, your continuous residence may be in question. See the N-400 application for naturalization overview for more detail on how absences affect your eligibility.
Basic information about your parents — whether they're U.S. citizens, their dates of birth, etc. This helps USCIS determine whether you may have derived citizenship through a parent (which would affect how your application is processed).
Your current marital status and a history of all prior marriages. If you've been married more than once, you must list each marriage with the name of the spouse, date of marriage, date of termination (if applicable), and how it ended (divorce, death, annulment). Include copies of divorce decrees or death certificates if you have prior marriages — USCIS may request them.
If you're applying on the 3-year path as a spouse of a U.S. citizen, the authenticity of your marriage will be examined closely. Evidence of joint residence, shared finances, and genuine partnership helps your case.
Information about all your children — biological, adopted, and stepchildren — regardless of age or citizenship status. USCIS uses this information to check whether any of your children may have derived citizenship through you as part of your naturalization (children under 18 who are permanent residents often automatically become citizens when a parent naturalizes). Include all children even if they're adults or already citizens.
This is the longest part of the N-400. It's a series of 44 yes/no questions covering your background, including:
Answer every question truthfully and completely. USCIS runs a background check using federal, state, and local criminal records databases. If you have any arrests — even dismissed charges, expunged records, or traffic incidents that resulted in a citation — answer those questions yes and include documentation. Lying on the N-400 is a federal offense and can result in deportation even after citizenship has been granted.
If any of your yes answers relate to criminal history, review the N-400 common pitfalls guide and consider consulting an immigration attorney before filing.
You sign and date the form certifying that everything you've written is true. Your signature also authorizes USCIS to release your name and address to state voter registration agencies, unless you opt out. Read this page carefully before signing.
If someone helped translate the form for you, they must complete this section with their information and sign.
If an attorney or authorized representative helped you complete the form, they complete this section. If you filed without assistance, leave this blank.
After reviewing a sample N-400 form, the most common places where people make errors are:
Incomplete travel history. Missing even one trip to Part 7 creates a discrepancy. Be thorough.
Leaving fields blank instead of writing N/A. If a question doesn't apply to you, write N/A. Don't leave fields empty — USCIS may treat blank fields as unanswered questions requiring follow-up.
Using abbreviations or incomplete names. Write out full names — no nicknames or initials unless that's your legal name.
Inconsistent dates across the form. If your employer's start date in Part 4 doesn't match what you've provided on tax returns or your green card application, USCIS will notice.
Checking the wrong eligibility box in Part 1. Verify your eligibility dates before you select anything. Use the USCIS physical presence calculator to confirm your days count before you start.
The N-400 required supporting documents practice questions cover what documentation supports each part of the application. Reviewing these before you gather your materials saves time. And for the civics test, the N-400 processing time guide explains what happens between filing and your ceremony so you know what to expect at each stage.
Now that you know what each section contains, the next step is to start gathering your documentation before you touch the form. Create a master checklist: tax transcripts or notices of assessment for the past 5 years, passport pages with entry and exit stamps, court records for any criminal history, and employment verification letters if your work history is complex.
With documents in hand, the form itself becomes much easier to fill out accurately. Don't guess on dates — verify them. Don't skip any question, even if the answer seems obviously no. And once you've filled it out, have someone you trust review it before you submit.
The N-400 application is the first step. After filing, you'll prepare for the civics and English tests. The N-400 civics test preparation materials here cover all 100 USCIS civics questions in the format you'll encounter in your interview. Start that preparation early — don't wait until after you receive your interview notice.