The Orangeville Public Library originated as the Orangeville Mechanics Institute (OMI), a members only organization around 1878. The OMI opened its doors to the public in 1895 and by the early 1900s was outgrowing its location. Library Board members and the Town of Orangeville worked together with the Andrew Carnegie Foundation to begin building a new library on the corner of Mill Street and Broadway. With a grand opening in April 1908, the officially renamed Orangeville Public Library began serving the community.
Other than a minor renovation to the children's room in 1967, the library building remained unchanged for almost 80 years. With increases in the Town's population, changes in technology and the growth of the collection, the Library underwent a major fundraising campaign and renovation in the late 1980's. The original Library building was united with the old Bank of Commerce building. The architect's skillful re-design and combination of the two buildings resulted in the Orangeville Public Library's Mill Street location we are familiar with today.
The building was designated under the Ontario Heritage Act in 2002. Its architecture is the only surviving example of Beaux-Arts Classicism in Orangeville, a major contributing factor to the Heritage building designation.
In 2004, community growth prompted the addition of a branch to the Library. The Alder Street branch was opened on the second floor of the Alder Street Recreation Complex.
Further renovations were undertaken in 2013 and 2016 to improve accessibility, update technology and provide community space at the Mill St. Building. Highlights included the addition of floor space and a community living room along with the creation of a spectacular children's area.