The current massive building that houses the institution was built in 1929 and constitutes an example of pure neoclassical architecture.

A new house for the seminary was made necessary by the destruction by fire of the former building in the same year, on the same present estate of the Laviolette Boulevard.

The large main doors were designed by the French ironwork artist that created the Monument of the Flame beneath the Arc de Triomphe of Paris.

The presence, above the door, of a Saint Joseph statue and a mast displaying the flag of Quebec also underlines the motto of the school.

It is named after Pierre Boucher, an early Canadian settler who studied under and worked with the Jesuit missions in Georgian Bay.

The Séminare houses a major service of historical archives, an important gateway to Trois-Rivières and Mauricie history.

The Service des archives du Séminaire de Trois-Rivières (ASTR) traces its own origins to 1918, when the authorities of the seminary asked a young priest, Abbot Albert Tessier, to act as archivist.