Becoming a US citizen is the final step of an immigration journey that often takes many years. But before you can apply, you must meet a specific set of requirements laid out in the Immigration and Nationality Act (INA). USCIS calls them the “eligibility requirements for naturalization,” and they fall into 9 main categories. Miss even one, and your application will be denied — or worse, it will be approved incorrectly and revoked later.

This guide is the complete 2026 checklist of every US citizenship requirement. Work through each section and check whether you qualify. If you clear all 9, you can file with confidence.

The 9 Core Requirements

1. Age requirement — at least 18
2. Permanent resident status
3. Continuous residence
4. Physical presence
5. State or USCIS district residence
6. English language ability
7. US civics knowledge
8. Good moral character
9. Attachment to the Constitution

Requirement 1: You Must Be At Least 18

On the day you file Form N-400, you must be 18 years old or older. You cannot file on your 17th birthday even if you qualify in every other way. There is one exception: children under 18 can derive citizenship automatically if they have a US citizen parent, but that is a different process (Form N-600, not N-400).

Requirement 2: Lawful Permanent Resident Status

You must already be a green card holder. Your green card must be valid and unexpired (or your renewal must be in progress). If you have conditional status (usually marriage-based CR1/CR2 or investor EB-5), you must first remove conditions with Form I-751 or I-829 before applying for citizenship.

Requirement 3: Continuous Residence

You must have lived in the US continuously since becoming a permanent resident. The required duration depends on your basis:

Continuous residence is different from physical presence. Continuous residence means you have not broken your connection to the US by moving abroad permanently. Physical presence is a strict count of days.

What breaks continuous residence?

• Trip of 6 months or more: USCIS presumes residence is broken. You can rebut with strong evidence (kept home, family, job, taxes in US).
• Trip of 12 months or more: Residence is automatically broken. Your eligibility clock resets to 4 years and 1 day after your return (5-year rule) or 2 years and 1 day (3-year rule).
• Declaring yourself a non-resident for tax purposes: A red flag.
• Filing Form N-470: A preservation form for certain work abroad — can preserve continuous residence for approved employees of US employers, researchers, or religious organizations.

Requirement 4: Physical Presence

You must have been physically inside the United States for at least half the required continuous residence period:

• 5-year applicants: 30 months (912 days) out of the past 5 years
• 3-year applicants: 18 months (548 days) out of the past 3 years

This is a strict day count. Add up every day you were in the US. Short trips abroad reduce your count. Use passport stamps and CBP records at i94.cbp.dhs.gov to reconstruct.

Requirement 5: State or USCIS District Residence

You must have lived in the state or USCIS district where you file for at least 3 months before filing. This is easy for most applicants — just avoid filing right after moving to a new state. If you just moved, wait 3 months.

Requirement 6: English Language Ability

You must be able to read, write, speak, and understand basic English. USCIS tests this at the interview with:

• Speaking: Evaluated throughout the interview as you answer N-400 questions
• Reading: Read 1 of 3 simple sentences aloud
• Writing: Write 1 of 3 dictated sentences

Requirement 7: Civics Knowledge

You must demonstrate basic knowledge of US history and government. The test is 10 questions from a list of 128, and you need 6 correct to pass. 65/20 applicants study only 20 questions.

Requirement 8: Good Moral Character

USCIS evaluates your “good moral character” (GMC) during the statutory period (5 or 3 years, depending on your basis). Certain acts make you automatically ineligible, while others require USCIS to weigh the facts.

Automatic permanent bars to citizenship:

• Conviction for murder
• Conviction for an aggravated felony (as defined in immigration law) after 1990
• Persecution, genocide, torture, or severe violations of religious freedom
• Participation in Nazi persecution

Automatic bar during the statutory period:

• Crimes involving moral turpitude
• Two or more offenses with total sentence of 5+ years
• Drug offenses (except a single offense of possession of 30g or less of marijuana)
• Habitual drunkard
• Illegal gambling
• Prostitution
• Polygamy
• Smuggling
• False testimony to obtain immigration benefit
• Confinement in jail for 180+ days during the period

Discretionary GMC issues (USCIS weighs case-by-case):

• Minor arrests and citations
• Driving under the influence (especially 2+ DUIs during the period)
• Failure to pay child support or alimony
• Failure to file tax returns or pay taxes
• Lying on immigration forms
• Selective Service failures for men aged 18–26

Requirement 9: Attachment to the Constitution

You must be willing to support and defend the US Constitution. This is usually demonstrated by taking the Oath of Allegiance. If you have organizational affiliations with groups that advocate the overthrow of the government (Communist Party, terrorist groups), you are ineligible.

Selective Service Registration (Men Only)

If you are male and lived in the US between ages 18 and 26 (since March 29, 1975) you were required to register for Selective Service. Failure to register is a GMC issue. Exception: men who entered the US after age 26 are not required to register.

If you were required to register and did not, USCIS will typically approve your case if you can show you were unaware of the requirement and registered as soon as you learned. Get documentation from sss.gov.

Tax Compliance

You must be current on all federal, state, and local taxes. If you owe:

• Set up an IRS payment plan and bring proof
• Pay off the debt before filing if possible
• Bring tax transcripts to the interview

Owing taxes is not an automatic bar, but unresolved tax debt can delay or deny your case.

The Complete Eligibility Checklist

3-Year Rule for Spouses of US Citizens

If you are married to a US citizen, you can apply after just 3 years as a permanent resident — if all of the following are true during all 3 years:

• Your spouse was a US citizen for the entire 3 years
• You have been married to the same US citizen spouse for the entire 3 years
• You have been living in marital union (residing together) the entire 3 years

If you divorce, separate, or your spouse loses citizenship during the 3 years, you fall back to the 5-year rule.

Military Service Exceptions

Military applicants have their own special rules:

• Peacetime service (1 year): Eligible after 1 year of honorable service
• Wartime service: Eligible from day one under INA section 329
• Fees waived for qualifying military applicants
• Physical presence requirements waived in many cases

Use Form N-400 with the military supplement N-426.

Frequently Asked Questions

Final Thoughts

The citizenship requirements look intimidating in a list, but most applicants meet all 9 without even realizing it. If you have been a responsible permanent resident — paying taxes, obeying laws, staying in the country — you are probably eligible right now. Run through the checklist above, organize your documents, and take the next step. Millions of people have stood exactly where you stand today. In a few months, you can stand in a ceremony room raising your right hand.