The Mackenzie Building, named after Prime Minister Alexander Mackenzie, was built to house the administrative and educational functions of Canada's first military college which opened in 1876. The 1877 annual report of the chief architect (T.S. Scott) for the Department of Public Works describes the building as "plain in design and substantial in character. The outer walls are built of local limestone with cut stone quoins, plinth, strings and drawings to windows and doors; the stonework is supplied and cut at the Kingston Penitentiary." Consistent with federal building during Scott's term as chief architect the design is of the Second Empire style although not as grandly elaborate as his other large public buildings. Perhaps it was felt that more sober interpretation would better harmonize with the existing buildings on the square and at the same time give a fittingly military appearance to the structure.