What are the USCIS A-Number and the Department of State (DOS) Case ID?

These are two different identifiers that appear throughout an immigration process in the United States. The USCIS A-Number, also known as the Alien Registration Number, is a unique number that U.S. Citizenship and Immigration Services (USCIS) assigns to individuals who enter the immigration system.

This number follows the person’s immigration history: it helps authorities locate records, track case progress, and share information across different government agencies. It typically appears in official letters and documents you receive during the process.

The Department of State (DOS) Case ID, on the other hand, is used by the U.S. Department of State to track the consular portion of a case, related to visa issuance at embassies and consulates abroad. In petitions such as the H-1B, it is common to deal with both: the A-Number on the USCIS side and the DOS Case ID on the consular side.

• USCIS A-Number: identifies the individual within the immigration history.
• DOS Case ID: identifies the visa case at the consulate or embassy.

Keep these numbers safe and verify information only through official government channels, avoiding any promises of quick results. If you have questions about your case, seeking specialized guidance is advisable.

About the author

Victoria Harper

Editor-in-Chief

Meet the author

As a journalist and lead editor at Visto n’ Visa, Victoria helps ensure that immigration topics are covered in a clear, trustworthy, and easy-to-understand way. Her focus is on delivering useful, human, and relevant content for people exploring new paths abroad.