Immigration status can be checked with application receipt number from the U.S. Citizen and Immigration Services, not an alien number.
An alien number cannot be used to check on your immigration status. Instead, use the application receipt number printed on the application noticed provided by the United States Citizenship and Immigration Service (USCIS) to verify your status. If you do not have the receipt number available, call USCIS at 1-800-375-5283 and explain your situation.
The Application Receipt Number
Visitors to the U.S. seeking a change of status, resident alien status (green card), employment authorization or citizenship must file a petition with the USCIS. When any application is made to the USCIS, the agency will respond with an application notice that will bear an application receipt number. The USCIS may also assign an alien registration number, or A#.
Check Your Status
To check the status of your case with an application receipt number, go to the USCIS page at https://egov.uscis.gov/ and click on the "Check Your Case Status" link. Enter your application receipt number, the 13-digit number that is found on notices you have received from the USCIS. The application receipt number begins with a series of three letters, either EAC, WAC, LIN or SRC. Enter all letters, numbers and characters, except for dashes. The screen will be updated with your current case status, which can be one of the following: Acceptance, Initial Review, Request for Evidence, Testing and Interview, Decision, Post-Decision Activity, and Document Production or Oath Ceremony.
If you are seeking current processing time for your petition, there is a second field on the page for this purpose. Enter the petition form number, then select the form sub-type if applicable, and then the field office where your petition is being processed. The system will reply with three numbers: the USCIS National Goal, the USCIS National Average and the Service Center current processing time.
You can create an account for automatic updates of your case status at the USCIC website (see Resources). Applicants as well as their representatives can receive case updates by text message to a mobile phone or by email.
The A Number
Your A# is a personal identifier assigned by the USCIS if you apply for an adjustment of status, for employment authorization, for a V visa and in certain other cases. The agency uses it to verify your identity in its internal processing systems. It is not used to identify individual petitions or filings.