The Model Colony History Room was established in the Ontario City Library in 1970. The room contains non-circulating materials concerning the social, economic and governmental history of Ontario and the western region of San Bernardino County. Materials include manuscripts, photographs, documents, maps, local school yearbooks, news clippings, Ontario city directories, and phone books. Many of these materials date back to 1882 when George Chaffey and William Chaffey founded Ontario, the "Model Colony."
The Ontario City Library's digital collection at California Revealed consists of still images, moving images, and audio recordings from the mid 1890s to the mid 1990s. The collection includes many oral histories, historical film footage of the Long Beach Earthquake of 1933, a 1947 film featuring Ontario locations and residents, and hundreds of historical photographs.