How can you find your naturalization certificate number?

The United States naturalization certificate number is printed with red ink on the top of all certificates of naturalization issued since September 27, 1906, according to the U.S. Citizenship and Immigration Services. Naturalization petitions filed after June 1906 may have a blank on the space for its naturalization certificate number.

Certificates with a blank space for its naturalization certificate number may have the number noted in a blank space at the back of the form, notes USCIS. In some cases, the certificate numbers can appear in indexes to court naturalization records. In this case, the certificate number should not be confused with the petition number on the form.