Is the mobile register the newspaper in to kill a mockingbird?

The Mobile Register, The Birmingham News, and The Montgomery Adviser are all papers that Atticus reads.

As for the official newspaper of Maycomb (Scout's hometown), that is The Maycomb Tribune. The Maycomb Tribune is smaller and less professional than the larger aforementioned papers. It's rumored that Mr. B. B. Underwood (owner, editor, and printer of The Maycomb Tribune) makes up each story in the quaint news source.