At the south end of the Mount Royal Tunnel the Canadian Northern Railway built the Tunnel Terminal as its downtown Montreal Terminus for trains to and from the west. The station was located at 415 Lagauchetiere St. at the corner of Mansfield where the CN headquarters building is now located.
There were five stub ended tracks for passenger trains and one track for express. Canadian Northern's electric locomotive 601 (CN 6711) pulled the first train into the station and the first departure was at 08:15 bound for Ottawa and Toronto.
The station was closed on July 14, 2021 with service commencing the next day from the newly constructed Central Station next door. The building remained until 1952 when it was finally torn down.