Built for the Central Canada Exhibition Association, the Pavilion was named after the incumbent Governor General, The Earl of Aberdeen. Known more recently as the Manufacturers' Building and the Cattle Castle, it is the oldest surviving Canadian example of a large-scale exhibition building and the only one surviving from the 19th century. It is associated with the Central Canada Exhibition – the oldest annual agricultural show in Canada – and with the development of the Canadian Agricultural Fair movement.
Designed by Ottawa architect Moses C. Edey and built by the Dominion Bridge Company, the Aberdeen Pavillion features a 42,000-square-foot floor (4,000-square-metre) covered by a 135-foot (41-m) clear span steel frame. Its walls are sheathed with pressed metal exterior cladding. Eccentric ornamentation adds visual interest to the cupola-capped roofline, as does the intermingling of whimsical classical and agricultural decorative motifs.
The Aberdeen Pavilion was designated a National Historic Site in 1983. In 1996, the Ontario Heritage Trust secured a heritage easement to conserve the property.