The main entrance to the Centre Block leads into the most important ceremonial spaces in the building: Confederation Hall and the adjoining Hall of Honour. Confederation Hall was planned as the central axis of the building, leading north through the Hall of Honour to the Library of Parliament, west to the Commons Chamber, and east to the Senate Chamber.
Confederation Hall is the main entrance foyer and focal point of the building's interior, and is remarkable for its grand architectural design, generous proportions and detailed sculptural program.
Designed in the Gothic Revival style, the hall has a massive central column supporting a magnificent fan vault ornamented with carved bosses, and recalls the exquisite interior of a medieval English chapter house. The lofty two-storey arcaded space is circular in shape. It is divided into eight bays, and is surrounded by a vaulted ambulatory, which supports the upper gallery. The pointed arches, carried by clustered limestone pillars and dark green syenite columns, are crowned with richly sculpted gables celebrating the confederated nature of Canada. An elaborate marble floor and large tracery windows, rising up to the gallery level, add to the hall's embellishment.
Confederation Hall was the last part of the Centre Block's interior to be constructed. Stonework on the Missisquoi Black marble base began on August 11, 1921, and the Tyndall limestone vault was completed the following December. It is interesting to note that a preliminary scale model of the hall was prepared as early as January 1918. The scale model was transferred to the stone shop where a full-scale wood-and-plaster model of the vault was then created in a purpose-built shed. This demonstrated the complexity of the stereotomy which would be needed to erect this type of vault. It was a fitting level of preparation and craftsmanship for what is arguably one of the country's greatest architectural treasures.