Eligibility Requirements for Naturalizing as a U.S. Citizen

Taking the First Step Toward U.S. Citizenship

Becoming a U.S. citizen is an important milestone and a dream come true for many green card holders. Naturalization brings many benefits, including the right to vote, travel freely, and access more opportunities. To qualify, you must meet specific eligibility requirements such as age, length of permanent residency, good moral character, English language skills, and knowledge of U.S. history and government.

Understanding these key criteria will help you prepare your application with confidence. We’re here to guide you through every step, making the process easier and helping you achieve your goal of becoming a U.S. citizen.

U.S. Citizenship Eligibility Requirements

To become a U.S. citizen, all naturalization applicants must meet certain eligibility requirements. These are the most common criteria for citizenship through naturalization. Some applicants, such as military service members or those with certain exemptions, may qualify under special rules. You can learn more about these special cases in our complete Naturalization Guide.

1. Be at least 18 years old.
2. Have continuously and physically lived in the U.S. as a green card holder for a required number of years.
3. Establish residency in the state or USCIS district where they plan to apply.
4. Demonstrate good moral character.
5. Be proficient in basic spoken and written English and show knowledge of U.S. history and government.
6. Register for military service if male and within the required age range, and be willing to perform civil service when needed.
7. Swear allegiance to the United States.

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Minimum Age

To apply for U.S. citizenship through naturalization, you must be at least 18 years old at the time you file your Form N-400. This ensures that applicants are legally considered adults and can take full responsibility for the Oath of Allegiance. An exception applies if you are applying based on wartime military service—there is no minimum age in that case.

Continuous and Physical Presence Requirements

To qualify for U.S. citizenship, you must meet both continuous residence and physical presence requirements. This is one of the most important eligibility criteria for U.S. citizenship, as failing to meet it could delay or even prevent your application from being approved.

Demonstrating Continuous Residence

Continuous residence means you have not taken any trips outside the United States lasting six months or more during the required period — five years as a permanent resident, or three years if married to a U.S. citizen.

Even if you took an extended trip abroad, you might still be able to overcome the presumption that your continuous residence was broken. Your chances will depend on several factors, including:

• Length of your stay outside the United States
• The strength of your reason for not returning sooner
• The USCIS officer’s discretion, since officers can still deny your application for other reasons — such as frequent international travel

If you are applying for naturalization based on certain periods or types of U.S. military service, you do not need to meet the continuous residence requirement. Check military members eligibility on naturalization guide to find out when they can apply for citizenship.

Also, remember that you can file your naturalization application up to 90 days before you complete the required three- or five-year wait. This can help you start the process sooner.

Proving Continuous Residence After Long Trips Abroad

If You Were Abroad for 181 to 364 Days

If you were outside the United States for more than six months but less than one year, USCIS may think you abandoned your permanent residence. To avoid having your citizenship application denied, you must show the USCIS officer that you did not intend to give up your U.S. residence during your time abroad.

You can do this by providing documents or proof that you kept strong ties to the United States, such as:

• Keeping your job in the U.S. and not working overseas
• Having close family members who stayed in the U.S.
• Keeping your home in the U.S.
• Keeping your children enrolled in a U.S. school

If You Were Abroad for 365 Days or More

If you stayed outside the U.S. for one year or longer, USCIS will automatically assume you gave up your permanent residence. This means your citizenship application will be denied, and you will have to wait before applying again:

• If your waiting period for citizenship is five years, you must wait at least four years and one day after returning to the U.S. before reapplying.
• If your waiting period is three years (for spouses of U.S. citizens), you must wait at least two years and one day after returning before reapplying.

How to Avoid Breaking Continuous Residence

If you’re planning to travel outside the United States for an extended time, it’s important to take steps before you leave to protect your permanent resident status. By planning ahead, you can avoid problems with your U.S. citizenship application later.

Here are your main options:

1. Apply for a Re-entry Permit
If you expect to be abroad for one year or more, file Form I-131 (Application for Travel Document) before you leave. You’ll need to provide your biometrics while in the U.S., but you can arrange to pick up the permit from a U.S. embassy or consulate in the country you’re visiting. If it’s an emergency trip, you can request expedited processing. A re-entry permit is valid for two years and cannot be extended, so make sure to return before it expires.

Note to Remember: Form I-131 is used to apply for two different types of travel documents: a re-entry permit and a travel permit (Advance Parole). While both allow you to return to the United States after traveling abroad, they serve different purposes. A re-entry permit is for current green card holders, while a travel permit is for individuals who have applied for a green card but have not yet received it.

2. Apply for Preservation of Residence
If your work requires you to stay abroad for a year or longer — and it’s a type of employment recognized by the U.S. government — you can request to preserve your residence for naturalization purposes. This involves filing Form N-470 with USCIS, in addition to applying for a re-entry permit.

3. Apply for a Returning Resident Visa
If you had to remain abroad unexpectedly for a year or more — for example, due to a medical emergency — and you did not get a re-entry permit before leaving, you may need a Returning Resident Visa. Contact your nearest U.S. embassy or consulate at least three months before your planned return. You’ll typically complete Form DS-117, attend an interview, and present evidence that your extended stay was beyond your control.

Demonstrating “Physical Presence”

To qualify for U.S. citizenship, you must meet the physical presence requirement. This means you must have lived in the United States for at least half of the required time: 913 days (about 2.5 years) out of the last 5 years, or 548 days (a little over 1.5 years) out of the last 3 years if you are married to a U.S. citizen. While you can take multiple trips abroad during this period, you must also maintain your continuous residence to ensure you meet both requirements.

Note: When calculating your physical presence, USCIS counts both the day you leave and the day you return as days spent in the United States. For instance, if you depart on March 10 and return on August 10, both dates will be included in your total days of “physical presence” in the U.S.

Meeting the Residency Requirement

This requirement is different from the continuous and physical presence requirements above.

In simple terms, residency means the place where you live and have made your home. To meet the residency requirement, you must have lived in the state or USCIS district where you plan to apply for citizenship for at least three months immediately before filing your naturalization application.

“State” also includes the following:

• The District of Columbia
• Puerto Rico
• Guam
• The U.S. Virgin Islands
• The Commonwealth of the Northern Mariana Islands

A “USCIS district” refers to the geographical area served by a particular USCIS field office, determined by your ZIP code. USCIS will generally consider your residency to be the location you list as your “current physical address” on Form N-400 — even if you are applying for naturalization up to 90 days early.

The address you provide should be the place where you’ve established your life — for example, where you registered to vote, pay taxes, or obtained a state ID or driver’s license. There are some exceptions. If you’re a student and still financially dependent on your parents or guardians, you may apply for naturalization either from where you attend school or from your family’s home.

Good Moral Character

When USCIS talks about “good moral character,” they simply mean that your behavior and actions are in line with what most people in your community would consider honest, responsible, and respectful. It’s not about being perfect — it’s about showing that you’ve been a law-abiding and trustworthy person.

USCIS reviews this requirement on a case-by-case basis, meaning they look at your individual history before making a decision. In most cases, they check your behavior during the three or five years before you apply for naturalization (depending on your eligibility category) until the day you take the Oath of Allegiance. They can also look further back in your past if they feel it’s necessary.

To meet the good moral character requirement, you generally must:

• Avoid serious crimes — for example, murder, illegal gambling, or committing immigration fraud.
• Be truthful during your naturalization interview — lying to a USCIS officer can affect your application.
• Stay away from repeated serious traffic offenses — receiving two or more DUI convictions in the review period can harm your application, unless you can show that you maintained overall good character despite the incident.

There are some exceptions for certain applicants with U.S. military service, which may allow different standards to apply.

English Proficiency and Civics Knowledge Requirements

As part of becoming a U.S. citizen, you must pass a two-part naturalization test:

1. English Language Test – Measures your ability to read, write, and speak basic English.
   • During your citizenship interview, the USCIS officer will ask you questions about your N-400 application to assess your speaking skills.
   • You will also be asked to read and write simple sentences in English.
2. Civics Test – Measures your knowledge of U.S. history and government.
   • The test is based on a list of 100 possible questions.
   • Most applicants will be asked 10 questions and must answer at least 6 correctly to pass.
   • Depending on your age and how long you’ve held your green card, you may only need to answer 20 specific questions.

Some applicants may qualify for exemptions from one or both tests. For complete details, including who qualifies, what to expect, and how to prepare, see our U.S. Citizenship Exam Guide with study resources and tips.

Military and Civil Service Registration

As part of the naturalization process, you must show your willingness to serve the United States if needed—either by joining the military or performing civil service. For most male green card holders between the ages of 18 and 26, this commitment is demonstrated by registering with the Selective Service System, which maintains a list of potential national emergency service members.

Note: Female applicants are not required to register with Selective Service.

Remember: When you applied for your green card, USCIS may have sent your information to the Selective Service automatically. However, if you’re unsure whether you’re registered or required to register, you can request a status information letter from the Selective Service confirming your registration status or exemption. To request a status information letter, you can visit the Selective Service website or contact their office by mail. This letter provides official proof of your registration status or exemption.

Who Must Register with the Selective Service for U.S. Citizenship?

You must register with the Selective Service System if all of the following are true:

• You are a male green card holder who lived in the United States at any time between the ages of 18 and 26.
• You must register within 30 days of turning 18, or within 30 days of becoming a green card holder if you are already between 18 and 26.

Who Does Not Need to Register with the Selective Service?

You generally do not have to register with the Selective Service System if you are male and any of the following apply to you:

• You are over 26 years old.
• You did not live in the United States at any time between the ages of 18 and 26.
• You lived in the U.S. during that age range but were here on a visa or another legal status (not as a green card holder).
• You were born between March 29, 1957, and December 31, 1959, when the Selective Service System was not active.

If you are unsure whether you need to register, it’s best to check directly with the Selective Service System to avoid delays in your citizenship process.

How and When to Register with the Selective Service?

If you are under 26 and haven’t registered with the Selective Service yet, do it before applying for U.S. citizenship to avoid delays or denial.

Ways to register with Selective Service:

• Online at the Selective Service System website
• At your local post office
• By mail using a registration card sent to you

You can check your registration online or by calling (847) 688-6888. Once registered, you will receive a Registration Acknowledgement Card—be sure to keep this card safe as important proof for your USCIS naturalization application, since USCIS may request it during the process.

What Will Happen If You Miss the Selective Service Registration Deadline?

If you are over 26 and haven’t registered with the Selective Service, you can no longer do so. Your next steps will depend on your age when you apply for naturalization. USCIS can deny your naturalization application if you refused or knowingly and willfully failed to register during the required period.

Citizenship Eligibility for Applicants Under 26 Years Old

If you are under 26 years old, failure to register generally makes you ineligible for naturalization. This is because you are still within the age range where registration is required, and not registering during this period is considered a serious issue.

Naturalization Considerations for Applicants Between 26 and 31 Years Old

If you are between 26 and 31 years old and failed to register, USCIS may find you ineligible. However, USCIS will give you an opportunity to explain or provide evidence that:

1. Your failure to register was not knowing or willful.
2. You were not required to register.
3. You were exempt from registering.
4. You did register, but USCIS or the Selective Service System (SSS) did not complete the registration process on your behalf.

USCIS will review the evidence you provide before making a final decision about your eligibility.

Important: As explained earlier, you can request a status information letter from the Selective Service to confirm your registration status or exemption. Be sure to send a copy to USCIS.

If you were unaware that you needed to register, you must provide USCIS with the following documents along with your status information letter:

• A notarized affidavit from yourself, where you clearly explain the reasons you did not know about the registration requirement.
• Notarized affidavits from other people who personally know you and can confirm your explanation.

Willful Failure to Register and Its Consequences

If you intentionally failed to register when required—whether by refusing or ignoring the obligation—USCIS may deny your citizenship application. However, your age at the time you apply will also be taken into account:

• If you are between 26 and 31 years old, USCIS will likely give you an opportunity to prove that you were not required to register or that you were exempt before making a final decision.
• If you are 31 or older (or 29 or older if married to a U.S. citizen), the failure to register may no longer disqualify you. Still, your refusal or neglect to fulfill this responsibility could be viewed as a lack of “good moral character”.

Citizenship Eligibility Rules for Applicants Over 31 Years Old

On the other hand, applicants who are over 31 years old are generally eligible for naturalization even if they knowingly and willfully failed to register. This is because the statutory period for registration has passed by that age, and the failure to register is no longer considered a disqualifying factor.

Allegiance to the United States

To become a U.S. citizen, you need to show that you believe in and support the U.S. Constitution. This means you agree to follow U.S. laws and are ready to help protect the country if needed.

After your application is approved and you pass your interview and tests, the last step is to attend a special ceremony called the naturalization ceremony. At this ceremony, you will take the Oath of Allegiance, which officially makes you a U.S. citizen.

Before you take the oath, you will be asked some questions to make sure you understand what you are promising. You will confirm that:

• You are taking the oath by your own choice.
• You promise to be loyal only to the United States and give up loyalty to any other countries you belong to.
• You understand the duties of being a U.S. citizen, including the possibility of serving in the military or doing other public service if needed, and you plan to do these duties.

Taking the Oath of Allegiance is the final step to becoming a U.S. citizen.

Ready to Begin Your Journey Toward U.S. Citizenship?

Meeting the eligibility requirements is just the start of your path to U.S. citizenship. With careful preparation and expert support from ImmigrationDirect, including access to trusted lawyer consultations, you can confidently navigate the naturalization process. Don’t wait—connect with us today to get personalized guidance and take the first step toward becoming a proud U.S. citizen. Your American dream is within reach, and we are here to help you make it happen!