Beginning of Bridge Construction (November 1932)
Construction of the bridge began in November 1932 and was completed in the early summer of 1934.

Built by the Dominion Bridge Company Limited under a government-funded work program devised to remedy the Depression, it was designed by 11 French-Canadian engineers, graduates of the École Polytechnique de Montréal.



Opened to Traffic (June 22, 1934)
It was opened to traffic on June 22, 1934, 10 months ahead of schedule.



Commissioners (August 14, 1922)
The Honoré Mercier Bridge was built for the Corporation du pont du lac Saint-Louis, whose commissioners were:

• The Honourable Raoul O. Groth, legal counsel, President

• J. Arthur Trudeau, Vice President

• Louis Chatelle, Secretary-Treasurer

• Gérald Fauteux, K.C., Assistant Treasurer

• Joseph Dupont

• Robert R. Ness

Tolls (1956)
The following tolls were charged to cross the bridge: 

• 50 for an automobile and driver;

• 05 for each additional passenger;

• 50 for a truck weighing 2,000 lbs (907.18 kg) or less and the driver;

• 80 for a truck weighing between 2,000 lbs (907.18 kg) and 4,000 lbs (1,814.36 kg) and the driver;

• $1.20 for a truck weighing between 4,000 lbs (1,814.36 kg) and 8,000 lbs (3,628.72 kg) and the driver;

• $1.80, $2.00, $2.40 and $3.00 for trucks weighing 10,000 lbs (4,535.90 kg), 12,000 lbs (5,443 kg), 14,000 lbs (6,350.26 kg) and 16,000 lbs (7,257 kg) respectively, and the driver.

Raising of the Bridge Sections Sraddling the Seaway (1958-1959)
In 1958-1959, the St. Lawrence Seaway Authority raised the sections of the bridge straddling the Seaway, which was under construction at the time. The spans on the south side, beginning at pier 14, were jacked up to provide clear passage for ships plying the Seaway. As a result, the raised part of the bridge, representing half of the bridge's length, is under federal jurisdiction.



A Second Bridge (August 1963)
The groundbreaking ceremony took place on May 26, 1925. Work at the Longueuil job site began the following day, with work at the Montreal site starting soon after.