Format breakdown - service center prefixes
The 3-letter prefix tells you which USCIS service center received your case:
- EAC - Vermont Service Center (Eastern)
- WAC - California Service Center (Western)
- LIN - Nebraska Service Center
- SRC - Texas Service Center
- NBC - National Benefits Center
- IOE - ELIS (electronic filing system, used for most online filings)
- MSC - National Benefits Center (older designation)
- YSC - Potomac Service Center
Where to find your receipt number
- I-797C Notice of Action - top portion, labeled 'Receipt Number'.
- myUSCIS online account - every filing displays its receipt number.
- USCIS email confirmations - sent within hours of a successful electronic filing.
- ASC appointment notices - biometrics letters print the receipt number.
How to track your case
Go to egov.uscis.gov/casestatus, type your full 13-character receipt number with no spaces or dashes, and click 'Check Status'. USCIS updates the status when an officer takes an action. Statuses range from 'Case Was Received' to 'Card Was Mailed'.
Receipt number vs alien number vs case number
- Receipt number - application-specific. New one for every petition you file.
- Alien (A) number - your permanent personal ID. Never changes.
- Case number - usually a synonym for receipt number, though immigration court uses 'case number' for a separate court docket ID (an A-number with 9 digits, no prefix).