Table of Contents
Introduction to the N-400
The N-400, Application for Naturalization, is the form used by lawful permanent residents to apply for U.S. citizenship. When filing an N-400 Application for Naturalization, every document matters. Missing a single piece of evidence can mean delays, RFEs, or even denials. But with the right guidance, you can submit a strong application and avoid unnecessary complications.
This guide is here to help. We draw from Pigeon’s years of experience working with immigration law firms and insights from AILA’s Immigration Law Practice and Procedure Manual: A “Cookbook” of Essential Practice Materials—an invaluable resource for immigration professionals.
We’ll walk you through the supporting documents you need for an N-400 petition and why optional evidence can strengthen your submission. Whether you’re an immigration attorney, legal assistant or paralegal managing case preparation, this breakdown will help you stay organized and confident.
Why Supporting Documents Are So Important
Think of supporting documents as the backbone of your N-400 petition. While the form officially declares your eligibility, the documents provide the proof.
Supporting documents serve three key purposes:
Prove eligibility: USCIS needs to verify that the applicant meets the legal requirements to file the petition.
Validate eligibility for naturalization: Documents confirm the applicant’s residency, good moral character, and other qualifications.
Provide extra assurance: Even optional documents can strengthen your case and preemptively address questions USCIS might raise.
How Pigeon Simplifies Document Collection
If you’re looking to streamline your supporting evidence collection process, check out Pigeon Documents, a platform built to do just that.
Keeping track of dozens of documents for an immigration case can be overwhelming. That’s where Pigeon comes in. Our platform makes the document collection process easier for immigration law firms and their clients.
Here’s how Pigeon helps:
Document Checklists: Create flexible supporting document checklists and save them as templates for each case type.
Simple Client Uploads: Clients receive a custom-branded email or SMS with a secure link to upload files, and they never need to create an account.
Automated reminders: Clients receive reminder notifications to keep them on track.
Track, Manage, and Request Changes: Submissions are organized in a dashboard, with tools to request changes or provide feedback.
With Pigeon, you can save time, reduce errors, and provide a seamless experience for your clients.
Get started with Pigeon today—schedule a demo or start your free trial now!
The Supporting Documents You Need for an N-400
General Documents for All Applicants
Proof of Legal Permanent Residency:
Copy of the front and back of the Green Card; or
Copy of the I-90 Receipt Notice (if the card is lost, expired, or expiring within six months).
Name Change Documents:
Copies of legal name change documents, such as a Marriage Certificate, Divorce Decree, Court Order of Name Change, etc. (if applicable).
Proof of Current Marital Status:
Marriage Certificate, Divorce Decree, Annulment Decree, or Death Certificate for a former spouse (if applicable).
Tax Documentation:
Federal Income Tax Returns or IRS Tax Return Transcripts for the past five years (or three years if applying as the spouse of a U.S. citizen).
Certified copies of IRS Income Tax Returns for the past three years (if applicable).
Travel History:
Copies of all pages of current and prior passports since becoming a Permanent Resident, including entry and exit stamps.
Copies of Travel Permits issued by USCIS (if applicable).
Selective Service Registration (if applicable):
Proof of registration (if male and between the ages of 18 and 26).
If not registered, submit:
A statement explaining the failure to register.
A Status Information Letter from the Selective Service System.
Criminal History:
Copies of Police Reports, Certified Court Dispositions, or statements from arresting agencies confirming no charges were filed (if applicable).
Documentation of completed alternative sentencing or rehabilitation programs, such as probation or parole records, if applicable.
Copies of court orders for any arrests or convictions that have been vacated, set aside, sealed, expunged, or removed.
Military Records (if applicable):
If currently serving:
Completed and Certified Form N-426.
Copy of official military orders.
If separated from service:
DD Form 214, NGB Form 22, or Discharge Orders.
If Applying Based on Marriage to a U.S. Citizen
Proof of Spouse’s U.S. Citizenship:
U.S. Birth Certificate.
Certificate of Naturalization or Citizenship.
Certificate of Report of Birth Abroad.
U.S. Passport (biometrics and signature pages).
Evidence of Cohabitation (if residing together for the past three years):
Joint IRS Tax Return Transcripts for the past three years.
Joint bank account statements.
Joint leases or mortgages.
Birth certificates of children (if applicable).
If Applying Based on Military Service under INA §328 or §329
If Currently Serving in the Military:
Completed and Certified Form N-426.
Copy of official military orders.
If Separated from Military Service:
DD Form 214, NGB Form 22, or Discharge Orders.
Additional Evidence to Consider Submitting
While not always required, submitting these documents can strengthen your case:
Proof of Current Domicile: Driver’s License or State-Issued ID showing your address.
Evidence of Maintaining U.S. Residency During Long Trips Abroad (if any trips were over six months):
Federal Tax Returns or IRS Tax Transcripts.
Documentation of ties to the U.S. during the trip (e.g., property ownership, continued employment).
Child Support Documentation:
Court or government orders showing compliance with financial support obligations.
Evidence of financial support provided even if no court order exists.
Notes on Submission for Criminal History
If the applicant has any arrests, citations, or convictions, they should:
Submit copies of all related police reports and certified court records.
Include proof of completion of any sentences, such as probation records or alternative sentencing program completion.
Bring originals or certified copies of these documents to the USCIS interview.
Example N-400 Checklist with Pigeon
With Pigeon, you can create flexible supporting document checklists and save them as templates for each case type. Already have existing document lists? No problem—we can upload them for you to create your custom Pigeon templates!
Your clients will receive a custom-branded email or text message with a secure link to their upload checklist. Best of all, they never need to create an account, making the process seamless.
Here’s an example N-400 supporting document list in with Pigeon:
What makes Pigeon stand out?
Automated reminders: Clients receive email notifications to keep them on track.
Mobile-friendly design: Optimized for clients to upload documents directly from their phones.
Submission tracking: Submissions are automatically organized and tracked in your team dashboard.
Provide Feedback: Easily verify or request changes with comments on submissions.
AILA’s Immigration Law Practice and Procedure Manual
While this guide provides a thorough explanation of the supporting documents needed for an N-400 petition, AILA’s Immigration Law Practice and Procedure Manual: A “Cookbook” of Essential Practice Materials includes step-by-step workflows, sample letters, suggested forms, and other resources to help immigration professionals manage cases with confidence.
You can purchase a copy of AILA's Cookbook here.
Make Document Collection Easy with Pigeon
Running an immigration practice is stressful enough without all the pains that come with collecting supporting documents from clients. With Pigeon, you can make this process easier for you, your paralegals, and your clients.
Book a demo to learn more, or test Pigeon out on our free trial. Try Pigeon today and take the headache out of document collection.
Get started with Pigeon today—schedule a demo or start your free trial now!