Derby Line is known for the Haskell Free Library and Opera House, a line house deliberately constructed on the international border and opened in 1904. The donors were a binational couple: Carlos F. Haskell was a local American businessman who owned a number of sawmills, while Martha Stewart Haskell was Canadian. The intent was that people on both sides of the border would have use of the facility, which is now a designated historic site. Patrons of the library from either side of the border may use the facility without going through border security.