Last updated: August 12, 2025.
By Asel Williams, Esq. · Columbia Law School · Licensed immigration attorney
The process of obtaining US citizenship is also known as “Naturalization”.
The naturalization process consists of multiple steps, beginning with determining eligibility and ending with taking the Oath of Allegiance.
This detailed guide will bring you through the process of applying for US citizenship using Form N-400, including eligibility requirements, the application process, the processing times, a list of required documents, along with pros and cons of becoming a US citizen.
Who’s Eligible to Apply for Citizenship?
Several requirements must be met before a permanent resident becomes eligible for US citizenship:
Age: You must be at least 18 years old when you file Form N-400.
Residency: You must have been a lawful permanent resident (green card holder) for at least 5 years (or 3 years if married to a US citizen) before you can file Form N-400.
Physical Presence: You must have been physically present in the United States for at least 30 months.
Continuous Residence: You must have lived continuously in the United States as a lawful permanent resident.
Good Moral Character: The applicant must have demonstrated good moral character.
English and Civics: Basic English reading, writing, and speaking skills are required, as well as knowledge of US history and government.
Attachment to the Constitution: Must demonstrate an attachment to the principles of the United States Constitution.
How to Apply for U.S. Citizenship
Applying for US citizenship consists of multiple steps:
Prepare Form N-400: Fill out the Application for Naturalization. Ensure that all areas are completed correctly. The form is available on the USCIS website. Form N-400 can be filed online or by mail.
Gather Supporting Documents: Gather all required documents, such as a copy of your green card, proof of federal tax returns filing, payment of federal tax returns, and proof of marital status (if applicable).
Submit Form N-400: Mail the completed form and any supporting documentation to the proper USCIS address. You can also file online via the USCIS website.
Pay the fees: The application fee is $710 (if filing online), or $760 (if filing by mail). Payment can be done with a check, money order, or credit card. Certain applicants may be eligible for a reduced filing fee of $380 if their annual household income is not more than 400% of the Federal Poverty Guidelines.
Biometrics Appointment: After submitting your application, you will be notified of a biometrics appointment where your fingerprints, photo, and signature will be collected. If you have previously submitted biometrics, USCIS may reuse your past biometric information and you will not be required to attend the new appointment.
Attend the Interview: You will be scheduled for an interview with a USCIS officer, who will evaluate your application and assess your English and civics knowledge.
Receive a Decision: USCIS will notify you of its decision. If approved, you will be scheduled for an oath ceremony.
Take the Oath of Allegiance: To formally become a citizen of the United States, you must attend the ceremony and take the Oath of Allegiance.
How Long Does it Take to Become a U.S. Citizen?
The length of the naturalization process varies and can take anywhere from 6 to 18 months, depending on your location and the volume of cases that the USCIS office is handling.
Below is an estimated naturalization processing timeline:
- Receipt Notice: 2-3 weeks after filing
- Appointment for biometrics: 5-8 weeks following filing.
- Exam and Interview: six to twelve months following filing.
- Oath Ceremony: if approved, 1-2 months following the interview. Some applicants attend the oath ceremony on the interview day.
Visit the USCIS Processing Times page and choose Form N-400 to get the most recent processing times.
US Citizenship Application Checklist
Submit the necessary documents to make sure the application process is not delayed:
Completed Form N-400: Verify that every field has been filled out accurately. Sign and date the form. If filing Form N-400 by mail, use the most recent edition of Form N-400 available on the official USCIS website.
Photograph: Two passport-style photographs (if you are located outside the United States).
Permanent Resident Card: Copy of front and back (Form I-551)
Proof of Marital Status:
- certificate of marriage, if married.
- decree of divorce, decree of annulment, or the former spouse’s death certificate.
Proof of Military Service: Please provide Form DD 214 or any other relevant military records, if applicable.
Court and Arrest Records: If you have been arrested or placed under arrest, certified copies of all arrest records, court rulings, and other related documentation are required.
Tax Returns: copies of the federal tax returns for the last five years (or three years if you are married to a citizen of the United States). Also submit proof of all federal tax payments. You can obtain this information on the IRS website.
Proof of bona fide marriage: if you are married to a US citizen, you might be requested to provide evidence of marriage. See the full checklist of acceptable documents here.
Form N-426: If applying based on qualifying military service.
Form N-648: Medical Certification for Disability Exceptions, only if you are requesting an exception to the English and civics testing requirements for naturalization because of physical or developmental disability or mental impairment.
What to Bring to Your N-400 Appointment
You will receive an appointment notice for an interview 4-5 weeks before the scheduled date.
Bring the following original documents to your interview:
- Appointment Notice: The USCIS notice of your appointment
- Identification: an original photo ID such as a passport or driver’s license.
- Permanent Resident Card: Your green card.
- Additional Documents: Any other documents listed on the interview notice, such as most recent federal tax returns, proof of federal income tax payments, etc.
- Original Documents: Bring the originals of all photocopied documents that you included with your Form N-400 (such as marriage certificate, divorce decree, etc.)
- Translation of Documents: If you have any documents that are in foreign language, bring certified English translation.
Pros and Cons of Applying for Citizenship
Pros:
Voting Rights: American citizens are entitled to vote in municipal, state, and federal elections.
Passport and Travel: Holders of a U.S. passport are not required to obtain entry visas to many foreign countries.
Federal Jobs: Certain federal jobs are only open to citizens of the United States.
Family Sponsorship: Green card applications for a larger variety of family members can be sponsored by citizens, and the procedure is frequently quicker. US citizens can sponsor their married sons and daughters, parents, and siblings.
Protection from Deportation: U.S. citizens cannot be deported.
Dual Citizenship: You can keep your original nationality in the United States if you choose to hold two citizenships.
Foreign Residency: US citizens can spend significant time abroad without risk of losing their immigration status. In contrast, permanent residents must reside in the US at least 6 months within 12 months, or longer, in order to avoid losing their permanent residency.
Cons:
Civic Responsibilities: US citizens are required to serve jury duty unless excused
Tax Obligations: Regardless of where they reside, US citizens are required to report their worldwide income and may be subject to US taxes.
Dual Citizenship: some foreign countries prohibit dual citizenship, so you might be forced to surrender your foreign passport.
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