The purpose of a copyright registration is to have a verified record of the date, owner, and content of a work. This protects the copyright owner in legal cases of plagiarism or infringement. The copyright registration number is assigned to a work by the U.S. Copyright Office after an application and fee are submitted.     


The copyright registration number is a twelve-character string that typically begins with a two or three letter prefix, such as “PA” or “PAU.” Zeros should be inserted between the prefix and the numerical portion of the number so that the total number of characters is 12.  


For example: TX0001234567 


To find the copyright registration number for a work after 1978 or verify if a work is in the public domain, you can search the U.S. Copyright Office’s Public Catalog here. Information on works before 1978 can be found in the U.S. Copyright Office’s Public Records Reading Room here