Your alien number, officially the Alien Registration Number, is a unique identifier the U.S. Citizenship and Immigration Services (USCIS) assigns to noncitizens after certain interactions with the immigration system. It appears on documents such as the Arrival-Departure Record (I-94), work permits (I-766), and permanent resident cards (I-551), and it is required on many USCIS forms to link records, track case status, and verify identity. This guide explains what the number looks like, how it is assigned, where to locate it, when it may change, and how to reference it accurately in official contexts.
What an Alien Number Is and Why It Matters
An Alien Registration Number is a case or receipt number that functions as a persistent identifier for an individual in U.S. immigration records. It is not a synonym for a visa number, passport number, or USCIS case number, although it may appear near those fields on forms. The number ties together applications, decisions, and enforcement records, allowing agencies and employers to locate a person’s immigration history quickly. Because it appears on official documents and is used in automated systems, using the correct alien number reduces processing delays and prevents record-matching errors.
How the Number Is Assigned
The alien number is generated when USCIS creates a case or issues a document, and its format has evolved over time. Historically, it appeared as a string of letters followed by numbers on older paper receipts and I-94 cards. Modern systems often produce numbers that are primarily numeric, and newer electronic records may display longer strings. Each number is unique within its system of origin, whether it is tied to a work authorization request, a visa application, or a permanent residence case. The number remains with a person across most adjudications, even if the underlying case type or status changes.
Typical Format Patterns
While exact patterns have changed across decades and datasets, modern alien numbers often include combinations of letters and numbers that help distinguish them from other identification fields. For informational purposes only, common historical and contemporary patterns include:
- Legacy paper I-94 receipts: Letters such as DHS followed by numbers (e.g., DHS123456789).
- Older alien registration receipts: Letters such as A followed by seven or eight digits (e.g., A12345678).
- Modern USCIS case numbers or electronic identifiers: Longer numeric strings or mixed strings (e.g., 12345678901).
Where to Locate Your Alien Number
You can find your alien number on specific immigration documents rather than on informal identification. Primary locations include the biographic information page of printed I-94 records, the front of Employment Authorization Cards (Form I-766), and Permanent Resident Cards (Form I-551). It also appears on approval notices, appointment letters, and electronic records accessible through the USCIS online account. When in doubt, check the field labeled Alien Registration Number, A-number, or USCIS Number on the document itself.
Document-by-Document Quick Reference
| Document | Field Label | Example Format |
|---|---|---|
| I-94 (paper or electronic) | USCIS Number or A-number | DHS123456789 or 12345678901 |
| Employment Authorization Card (I-766) | USCIS Number | 000123456789 |
| Permanent Resident Card (I-551) | Receipt Number or A-number | A12345678 or 12345678901 |
| USCIS Form I-797 or I-140 notices | Case Number or A-number | AB-1234567 or 12345678901 |
When the Alien Number Can Change
For many people, the alien number assigned during an early admission or application remains consistent across documents. However, certain events can trigger a new number or a new appearance on a document. For example, when replacing a lost or stolen work permit, a new I-766 may display a different case number while referencing the same underlying alien number. Conversion between status, such as adjusting to permanent residence, can produce a new document with a distinct case identifier even though the person’s A-number often remains the same. Significant data corrections or system migrations may also result in updated record displays, so apparent changes are not always substantive.
Common Mistakes and How to Avoid Them
Confusing the alien number with a visa number, passport number, or USCIS case number is common and can cause form rejections or lookup delays. Always copy the exact string shown in the designated field on the document, preserving any leading zeros or letters. When entering the number online, use the proper box labeled A-number or Alien Registration Number, and double-check each character. If a document lacks an explicit alien number, contact USCIS customer service or your representative for guidance rather than substituting another identifier. Maintaining a small record of which document shows which number helps streamline future applications and inquiries.
Using the Number Correctly in Forms and Interactions
Provide your alien number on USCIS forms exactly as it appears on the underlying document, typically in the field marked A-number, USCIS Number, or Alien Registration Number. Include it when filing extension requests, status adjustment applications, and certain benefit claims, and share it with employers or agencies only when their policies explicitly require it. If you reference the number in supporting letters or inquiries, quote it verbatim and attach a copy of the source document for cross-checking. When in doubt about whether a specific field expects the alien number or a different identifier, consult the form instructions or an accredited representative before submission.
Summary of Key Identifiers
Keep these points in mind to avoid confusion between similar identifiers:
- The alien number is a unique immigration identifier assigned by USCIS, distinct from passport and visa numbers.
- It can be alphanumeric and appears on key documents such as I-94, I-766, and I-551.
- Its location on each document is labeled as Alien Registration Number, USCIS Number, or A-number.
- While persistent across many records, it may generate a new case number on replacement documents.
- Always copy the exact format, verify against the source document, and use it in the designated form fields.
Conclusion
Understanding your alien number and where it appears helps you manage immigration forms, avoid processing delays, and maintain accurate records. By knowing how the number is assigned, where to locate it, and how to enter it correctly, you reduce the risk of mismatched records and unnecessary follow-ups. Treat it as one component of a broader set of identifiers—passport, visa, and case numbers—and reference it deliberately in any official interaction that requests U.S. immigration identification.
Additional Context and Related Considerations
Because immigration systems link multiple records under the same alien number, it serves as an anchor for case histories, inspection data, and enforcement information. Employers running employment eligibility verification, attorneys reviewing case files, and agencies updating databases all rely on an exact match to the number on the document. When reviewing your own records, compare the number across documents to confirm consistency, and report discrepancies to USCIS promptly through the appropriate channels.
Authoritative Guidance and Next Steps
For the most current details on formats, field labels, and document-specific locations, consult the official USCIS website and the instructions for each form you complete. If you cannot locate the alien number on a document or see inconsistencies between records, contact USCIS customer service or seek help from an accredited representative. Keeping scanned copies of the relevant pages and a short log of when and where you used each identifier simplifies future applications, references, and compliance checks.