The Billiard Room: a distinctive feature is the octagonal timber-lined roof. V-jointed boards slope upwards to form a roof lantern providing natural light. Previously the roof was varnished with a dark wood stain, appropriate for relaxed, informal gatherings. The room has access from both State and private sections of the house.

Among the furniture made by Alcock and Company are the billiard table and revolving cue rack, the glass-panelled cedar bookcase to the right, and in the foreground the blackwood table crossbanded with inlaid Australian timbers. The suite of walnut chairs, including an armchair, were originally situated in the Council Room. On the Belgian 'St Anne' marble mantelpiece is a 19th century urn-shaped ceramic vase on loan from the National Trust of Australia (Victoria).

Raised benches on the side walls have been replaced by long book cases, reflecting the room's current use. The collection of books being compiled on Australian history and on the State's heritage is consulted by the Governor and his staff. An engraving of Lieutenant-Governor Charles La Trobe is on the back wall.