The Haskell Free Library and Opera House sits astride the international boundary between the United States and Canada. One part of the building is in Derby Line, Vermont and the other is in Stanstead, Quebec (which includes the former town of Rock Island). A black line runs through the building to designate the border. The Library and Opera House was deliberately built on the border with a gift from Martha Stewart Haskell and her son, Colonel Horace Stewart Haskell. It was dedicated to Mrs. Haskell’s late husband, Carlos. The building was completed in 1904. The initial intent was that the proceeds from the Opera House would support the operation of the Library. The Library and Opera House are operated as a non-profit corporation. The use of the library is free just like any public library.