Preparing your citizenship application? Get the complete N-400 checklist – all required documents list, application tips and processing timeline in SelfLawyer’s N-400 guide.

If you’re an immigrant and are looking forward to becoming a citizen of the United States, you may apply for U.S. citizenship through a process known as Naturalization, by meeting certain eligibility requirements.

Following this, the application of citizenship through this naturalization process requires you to fill a USCIS form, called the ‘Application for Naturalization’ or Form N-400.

We will shed more light on what ‘naturalization’ is, what to expect from the Form N-400, who can apply for, and most importantly, the supporting documents you must attach while submitting this Application of Naturalization, to apply for U.S. citizenship.

Here is a brief overview of all the supporting documents you will be expected to submit along with your N-400 form:

  • A copy of your Permanent Resident Card, or Green card
  • A copy of your marriage certificate (if applicable)
  • Proof that all your prior marriage(s) have come to an end (if any)
  • Form N-426, Request for Certification of Military or Naval Service (if applying for naturalization based on military service)
  • DD Form 214, NGB Form 22, or discharge orders (if applying for naturalization based on military service and separated from service)
  • A copy of your official military orders (if applying for naturalization based on military service and currently serving)
  • Evidence of your citizen spouse’s employment abroad (if applying under 319(b))
  • Two identical passport-style photographs (if you reside outside the United States)

What is Form N-400?

N 400

Form N-400, Application for Naturalization, is an application issued by the government for foreign born individuals to become a naturalized U.S. citizen.

This means that before understanding the N-400 form, you need to have a basic understanding of the term ‘naturalization’.

Naturalization refers to the process in which a person not born in the United States voluntarily becomes a U.S. citizen. However, only certain individuals are eligible for this.

If you wish to apply for naturalization, you should use the “Application for Naturalization” or Form N-400. For foreign-born persons, naturalization is the most common way to become a U.S. citizen. 

If your biological or legal parent is a U.S. citizen by birth, or was naturalized before you reached your 18th birthday, you may already be a U.S. citizen.

To help you understand the naturalization process in depth, the USCIS has developed a guide that provides information on eligibility requirements and naturalization procedures. You can check it out here.

Who Can File Form N-400?

As stated earlier, one can file for citizenship via the naturalization process by filling the Form N-400 but this is applicable only to a handful of immigrants, essentially the ones who meet certain eligibility criteria.

This implies only those foreign born applicants who have satisfied the eligibility requirements of naturalization can file the N-400 form.

General Eligibility Requirements for Naturalization

It is important that you satisfy all of these conditions for naturalization, if you wish to successfully file the Form N-400, to apply for U.S. citizenship.

  • You are at least 18 years of age at the time of filing (except active duty members of the U.S. Armed Forces)
  • You are a permanent resident of the United States for the past 5 years and have no special circumstances
  • You have lived within the state or USCIS district where you claim residence for at least 3 months prior to filing
  • You have demonstrated physical presence within the United States for at least 30 months
  • Currently married to and living with a U.S. citizen and have been married to and living with that same U.S. citizen for the past 3 years
  • Currently serving in the U.S. Armed Forces (or will be filing your application within 6 months of an honorable discharge) and have served for at least 1 year
  • You have demonstrated continuous residence for a required period of time
  • You demonstrate a good moral character
  • You demonstrate an attachment to the principles and ideals of the U.S. Constitution
  • You demonstrate a basic knowledge of U.S. history and government , along with the ability to read, write, speak and understand basic English
  • You take an Oath of Allegiance to the United States.

How to File Form N-400?

There are generally two options for filing your Form N-400 with USCIS.

  • Online, or 
  • By mail (paper)

Filing N-400 Form Online

You may file your N-400 online, unless you’re applying:

  • based on your military service, or
  • from outside of the U.S., or
  • for a fee waiver or reduced fee.

Only for the above three cases, you cannot apply the N-400 form online. For these cases, you’ll have to file your form by mail.

To apply online, you must create an online account with the USCIS and sign your application electronically (by typing your full name at the end of the application). 

We have listed the details of the same here.

Filing your Form N-400 by Mail


If you’re filing your Form N-400 through mail, the USCIS address you must send your form and all the supporting documents shall vary depending upon the state in which you live and the delivery service you choose (U.S. Postal Service vs. FedEx, UPS, or DHL).

If you’re applying based on you (or your family member’s) military service, you will send your N-400 materials to a special address, again depending on the delivery method you choose.

The USCIS provides a list of all the addresses to which applicants must send their N-400. You can find the suitable address here

Make sure you sign your form before submission. The USCIS will reject any form that is unsigned.

Note: We advise you that once you complete filling your Form N-400, create a copy of it before you submit it to USCIS. This is because your citizenship interview will largely focus on the answers you provide on your naturalization application. So you can review those answers before attending your interview.

N-400 Checklist

All naturalization applicants must include supporting documents with their Form N-400. If you file your application online, you will need to upload digital copies (scans or photos) of these documents to your online USCIS account.

All applicants must attach the following items with their N-400 form:

Items to submit Notes
A photocopy of both sides of your Permanent Resident Card, or ‘Green Card’.
A check or money order for the application fee and the biometric services fee.
If you file for your form from outside the U.S., submit 2 identical color photographs
  • Write your name and A-Number lightly in pencil on the back of each photo.


If an attorney or an accredited representative is acting on your behalf, send:

  •  A completed original Form G-28, Notice of Entry of Appearance as Attorney or Representative.

If you are applying for naturalization on the basis of marriage to a U.S. citizen, send the following documents:

Type of document Examples of acceptable documents
Proof that your spouse has been a U.S. citizen for at least 3 years, send one of these documents
  • Birth certificate, or
  • Certificate of Naturalization, or
  • Certificate of Citizenship, or
  • The inside of the front cover and signature page of your spouse’s current U.S. passport, or
  • Form FS-240, Report of Birth Abroad of a Citizen of the United States of America.
Proof of your current marital status
  • Marriage certificate
Proof of termination of all your prior marriage(s):
  • Divorce papers,
  • Annulment(s), or 
  • Death certificate(s)
Financial records of your and your spouse
  • Tax returns, bank accounts, leases, mortgages, or birth certificates of children, or
  • Internal Revenue Service (IRS) certified copies of income tax forms filed by you both for the past 3 years, or
  • An IRS tax return transcript for the last 3 years.

If you are currently serving in the U.S. military service and are seeking citizenship on the basis of this service, send

  • A completed original Form N-426, Request for Certification of Military or Naval Service.

In case you have visited outside the United States, or taken a trip for over 6 months after becoming a Permanent Resident, send evidence that you continue keeping ties to the United States, like:

  • IRS tax return transcript depicting tax information for the last 5 years.
  • Rent or mortgage payments and pay stubs.

If you have a dependent spouse or child/children not living with you, send:

Type of document Examples of acceptable documents
Proof of financial support obligations fulfillment, and
  • Court or government order providing financial support
Proof citing your financial support
  • Cancelled checks,
  • Money and receipts
  • A court or agency printout of child support payments;
  • Evidence of wage garnishments;
  • Letter from the guardian caring for your child/children.

If you have ever been arrested or detained by any law enforcement officer, and no charges were filed, send:

  • An original official statement by the arresting agency or applicant court confirming that no charges were filed.

If you have ever been arrested or detained by any law enforcement officer and charges were filed, send:

  • An original or court-certified copy of the complete arrest record and disposition for each incident, like dismissal order, conviction record or acquittal order.

If you’ve ever been convicted or placed in a sentencing or rehabilitative program, like drug treatment or community service program, send:

  • An original or court-certified copy of the sentencing record for each incident
  • Evidence that you completed your sentence.

If you still haven’t filed an income tax return since becoming a Lawful Permanent Resident, send:

  • All correspondence with the IRS regarding your failure to file.

If you have any Federal, state or local taxes that are overdue, send:

  • A signed agreement from the IRS or state or local tax office showing that you have filed a tax return and arranged to pay the taxes you owe, and
  • Documentation from the IRS or local tax office depicting the current status of your repayment program.

If you are applying for a disability exception to the testing requirement, send:

  •  An original Form N-648, Medical Certification for Disability Exceptions, completed less than 6 months ago by a licensed medical or osteopathic doctor or licensed clinical psychologist.

If you have not registered with the Selective Service, provided you are a male of 26 years of age or older, and have lived in the United States not as a lawful nonimmigrant from ages between 18 and 26, then send:

  • A ‘Status Information Letter’ from the Selective Service. Call 1-847-688-6888 for more information on this.

Note: As per the USCIS, a ‘lawful nonimmigrant’ refers to:

  • An alien in a lawful status classified under the nonimmigrant statutory provisions, and
  • An alien in temporary protected status.

Lawful nonimmigrant status does not include parolees, asylees, or certain other aliens who are otherwise authorized to be physically present in the United States.

Form N-400 Processing Time

Application center Processing time
Agana GU 7.5 Months to 17 Months
Albany NY 7.5 Months to 17 Months
Albuquerque NM 5 Months to 5.5 Months
Anchorage AK 7.5 Months to 17 Months
Atlanta GA 4.5 Months to 27 Months
Baltimore MD 7 Months to 23.5 Months
Boise ID 7.5 Months to 17 Months
Boston MA 5.5 Months to 13 Months
Brooklyn NY 9.5 Months to 17.5 Months
Buffalo NY 4.5 Months to 8.5 Months
Charleston SC 7.5 Months to 17 Months
Charlotte Amalie VI 7.5 Months to 17 Months
Charlotte NC 5 Months to 15 Months
Chicago IL 5.5 Months to 15 Months
Christiansted VI 7.5 Months to 17 Months
Cincinnati OH 7.5 Months to 17 Months
Cleveland OH 4 Months to 6.5 Months
Columbus OH 5 Months to 8 Months
Dallas TX 10.5 Months to 39.5 Months
Denver CO 6 Months to 12.5 Months
Des Moines IA 7.5 Months to 17 Months
Detroit MI 6 Months to 11 Months
El Paso TX 5 Months to 7.5 Months
Fort Myers FL 5.5 Months to 8.5 Months
Fort Smith AR 7.5 Months to 17 Months
Fresno CA 5 Months to 7.5 Months
Greer SC 7.5 Months to 17 Months
Harlingen TX 4.5 Months to 6.5 Months
Hartford CT 8.5 Months to 21.5 Months
Helena MT 7.5 Months to 17 Months
Hialeah FL 3.5 Months to 8 Months
Honolulu HI 6 Months to 12.5 Months
Houston TX 13.5 Months to 45 Months
Imperial CA 7.5 Months to 9.5 Months
Indianapolis IN 7 Months to 13.5 Months
Jacksonville FL 5.5 Months to 11 Months
Kansas City MO 7.5 Months to 17 Months
Kendall FL 4.5 Months to 10 Months
Las Vegas NV 10.5 Months to 19.5 Months
Lawrence MA 7.5 Months to 17 Months
Long Island NY 7 Months to 18.5 Months
Los Angeles CA 7.5 Months to 17 Months
Los Angeles County CA 7.5 Months to 17 Months
Louisville KY 7.5 Months to 17 Months
Manchester NH 7.5 Months to 17 Months
Memphis TN 7.5 Months to 17 Months
Miami FL 7.5 Months to 26.5 Months
Milwaukee WI 7.5 Months to 17 Months
Minneapolis-St. Paul MN 8.5 Months to 16 Months
Montgomery AL 5.5 Months to 16 Months
Mount Laurel NJ 7.5 Months to 14 Months
Nashville TN 9 Months to 15 Months
Newark NJ 10 Months to 18 Months
New Orleans LA 8 Months to 21 Months
New York City NY 12.5 Months to 28 Months
Norfolk VA 7.5 Months to 11 Months
Oakland Park FL 4 Months to 16.5 Months
Oklahoma City OK 6 Months to 9.5 Months
Omaha NE 5 Months to 12.5 Months
Orlando FL 7.5 Months to 13 Months
Philadelphia PA 8 Months to 14.5 Months
Phoenix AZ 6.5 Months to 12 Months
Pittsburgh PA 7.5 Months to 17 Months
Portland ME 7.5 Months to 17 Months
Portland OR 7 Months to 12 Months
Providence RI 7.5 Months to 17 Months
Queens NY 10 Months to 15.5 Months
Raleigh NC 4 Months to 7.5 Months
Reno NV 7.5 Months to 17 Months
Sacramento CA 7.5 Months to 17 Months
Saint Albans VT 7.5 Months to 17 Months
Saint Louis MO 5.5 Months to 8.5 Months
Salt Lake City UT 7 Months to 16.5 Months
San Antonio TX 6 Months to 9.5 Months
San Bernardino CA 7.5 Months to 17 Months
San Diego CA 7.5 Months to 17 Months
San Fernando Valley CA 7.5 Months to 17 Months
San Francisco CA 7.5 Months to 17 Months
San Jose CA 7.5 Months to 17 Months
San Juan PR 7.5 Months to 17 Months
Santa Ana CA 7.5 Months to 17 Months
Seattle WA 11 Months to 19 Months
Spokane WA 7.5 Months to 17 Months
Tampa FL 5 Months to 11 Months
Tucson AZ 7.5 Months to 17 Months
Washington DC 9 Months to 21 Months
West Palm Beach FL 7 Months to 11.5 Months
Wichita KS 7.5 Months to 17 Months
Yakima WA 7.5 Months to 17 Months

Related links:

Apply for Citizenship – Complete Guide [2020]

U.S. Citizenship Application – Complete Guide [2020]

How Much Does it Cost to Become a US Citizen? [2020]