what is a number uscis

An Alien Registration Number (A-Number) is a 7-9 digit number that U.S. Citizenship and Immigration Services (USCIS) assigns to most immigrants who apply to live in the United States permanently, as well as certain student immigrants. It is also called a USCIS Number and is used to track immigrants' files and to provide on most immigration documents. The A-Number is found on the immigrant data summary, USCIS Immigrant Fee handout, or immigrant visa stamp, and is used for various immigration processes and to track an individual's immigration history