The building was designed by Thomas Fuller, Dominion Chief Architect for the Department of Public Works, and was the first Post Office and Customs House in Orillia. The brick is "Milton Brick" and local limestone from the quarries was used and it was built by J.R. Eaton of Orillia, a prominent local builder between 1892 and 1894. In 1913/14 the Tower and Mansford Roof were added during other renovations at that time. In the 1916 the Clock and Bells were added. In 1932 extensive renovations to the interior were done to make better use of the space inside the building. More renovations were done in 1935 and again in 1938.

In 1956 the City of Orillia purchased the building itself and it became the local Police Station and it also held the Magistrates Court here. The downstairs' cell blocks were added in 1960. It was designated as a Heritage Building in 1996. The Sir Samuel Steele Art Gallery began in 1994 in the building and now the building is going through another renovation and is under the direction of the amalgamated association of the Orillia Historical Society and the Sir Samuel Steele Art Gallery known as the Orillia Museum of Art and History. It is hoped that the fund raising for the new museum will continue and that the museum will be able to go back into the upgraded building in the future.