Understanding Your Alien Registration Number (A-Number) Brad Bernstein explains what an Alien Registration Number (A-Number) is, where to find it, and its significance in U.S. immigration processes. 📌 What is an Alien Registration Number (A-Number)? • A unique seven-, eight-, or nine-digit identifier assigned to non-citizens by the U.S. Citizenship and Immigration Services (USCIS). • Used to track your immigration records across various agencies. 📌 Where Can You Find Your A-Number? • Permanent