Most lawful permanent residents become eligible to apply for U.S. citizenship after five years with a green card, or three years if they are married to and living with a U.S. citizen. The process is called naturalization, it runs through Form N-400 filed with U.S. Citizenship and Immigration Services (USCIS), and it ends with an interview, an English and civics test, and the Oath of Allegiance. The legal requirements come from the Immigration and Nationality Act, principally INA 316.
The process is genuinely doable without drama for most applicants, but it is also a full re-examination of your immigration history. Here is what the path looks like and where people run into trouble.
Who is eligible to apply for naturalization?
The baseline requirements for the standard five-year track:
Age and status. You must be at least 18 and a lawful permanent resident. You can file up to 90 days before your five-year (or three-year) anniversary as a permanent resident.
Continuous residence. You must have resided continuously in the U.S. as a permanent resident for the five years before filing (three under the marriage rule). A trip abroad of more than six months creates a presumption that you broke continuous residence, which you can rebut with evidence of ongoing ties. A trip of a year or more breaks it outright absent special protections.
Physical presence. You must have been physically inside the U.S. for at least half the statutory period: 30 months out of the last five years, or 18 months out of three. This is a day-counting exercise, and frequent travelers should count carefully before filing.
State residency. You must have lived in the state or USCIS district where you file for at least three months.
Good moral character. USCIS looks at the statutory period, and can look further back. Certain convictions are permanent bars, most notably murder and aggravated felonies. Other issues, including some criminal offenses, unpaid taxes, failure to pay court-ordered child support, and false claims to citizenship or unlawful voting, can result in denial. Men who lived in the U.S. between ages 18 and 26 are generally expected to have registered for Selective Service.
English and civics. You must be able to read, write, and speak basic English and pass a civics test, subject to age and disability exceptions discussed below.
The three-year marriage track adds its own conditions: you must have been married to and living with your U.S. citizen spouse for the full three years, and the spouse must have been a citizen that entire time.
How long does the citizenship process take?
Processing times vary by field office and shift year to year, but the typical arc from filing to oath has generally run somewhere in the range of six months to a little over a year. The sequence looks like this:
- File Form N-400, online or by mail, with the filing fee (under the fee schedule adopted in 2024, the fee was 710 dollars for online filing and 760 dollars on paper, with reduced-fee and fee-waiver options for lower-income applicants; check the current amount before filing).
- Biometrics. Many applicants now have prior fingerprints reused; others attend a short appointment.
- The interview notice, typically several months later.
- The interview and tests at your local field office.
- The decision: granted, continued (usually for more documents or a retest), or denied.
- The Oath of Allegiance at a naturalization ceremony, which is the moment you actually become a citizen. Some offices administer the oath the same day; others schedule a separate ceremony weeks later.
What happens at the naturalization interview and test?
An officer places you under oath and goes through your N-400 line by line: your addresses, trips abroad, employment, marriages, children, tax history, and the long series of yes-or-no questions about criminal history, immigration violations, and attachment to the Constitution. The officer is verifying eligibility and also evaluating your spoken English through the conversation itself.
The English test has reading and writing components: you read one sentence aloud correctly and write one sentence correctly, from standardized vocabulary lists USCIS publishes.
The civics test covers U.S. history and government. Under the version in longstanding use, the officer asks up to 10 questions from a published list of 100, and you pass by answering 6 correctly. All the questions and answers are public, and USCIS publishes free study materials, so this is a preparation problem rather than a difficulty problem.
If you fail the English or civics portion, you are not denied on the spot. You get a second appointment, generally 60 to 90 days later, to retake the failed portion.
Two important exceptions: the 50/20 and 55/15 rules exempt applicants from the English requirement if they are 50 or older with 20 years as a permanent resident, or 55 or older with 15 years, allowing the civics test in their native language. The 65/20 rule allows a simplified civics study list. Applicants with a qualifying medical disability can seek an exception using Form N-648 completed by a doctor.
What can cause a naturalization application to be denied?
The most common problems fall into a few buckets:
Continuous residence and physical presence math. Long trips abroad, or a pattern of living mostly outside the U.S., sink more applications than any test does. If your travel history is heavy, count your days precisely and keep evidence of U.S. ties.
Good moral character issues. Arrests and convictions during the statutory period, unfiled or unpaid taxes, child support arrears, and misrepresentations. Two points matter here. First, disclose everything; a concealed arrest discovered by USCIS is far worse than a disclosed one that was dismissed. Second, some criminal issues do not just cause denial, they can expose an applicant to removal proceedings, because the naturalization file review re-opens your entire immigration history. Anyone with a criminal record, a prior fraud issue, or extended absences should get a professional opinion before filing, not after.
Selective Service. A willful failure to register can affect good moral character for men who were required to register, though its impact fades with age.
Errors and inconsistencies. Answers on the N-400 that contradict earlier filings, such as the green card application, invite scrutiny. Consistency across your immigration record matters.
A denial is not necessarily the end. You can request a hearing before a different officer using Form N-336, and in many cases the underlying problem, like a not-yet-satisfied residence period, simply resolves with time and refiling.
What are the benefits and obligations of citizenship?
Citizenship brings the right to vote in federal elections, a U.S. passport, protection from removal, the ability to sponsor a broader set of family members, and eligibility for federal jobs and benefits reserved for citizens. Children under 18 who are permanent residents living with a naturalizing parent generally become citizens automatically when the parent naturalizes.
The obligations are the ones in the oath: support the Constitution, and where required, serve on juries and register for military service if the law ever demands it. Note that U.S. citizens are taxed on worldwide income, a point that matters for people who keep significant ties abroad, and some countries restrict dual nationality, so it is worth checking your home country's rules before you take the oath.
For most eligible permanent residents, the smart preparation is simple: verify the day counts, pull your tax transcripts, list every trip abroad from the last five years, study the published civics questions, and file a clean, complete, honest N-400.