The Gulf, Mobile and Ohio (GM&O) Passenger Terminal, also known as the GM&O Building or Union Station, is a historic train station in Mobile, Alabama. Designed in the Mission Revival style by P. Thorton Marye, it was built in 1907 and served as the corporate headquarters and home terminal for the GM&O Railroad. The building is now home to various tenants, including government agencies and businesses, and is a significant architectural landmark in Mobile.