Haskell Free Library and Opera House

The Haskell Free Library and Opera House (French: Bibliothèque et salle d'opéra Haskell) is a Victorian building that straddles the Canada–United States border, in Rock Island (now part of Stanstead), Quebec, and Derby Line, Vermont, respectively. The Opera House opened on June 7, 1904, having deliberately been built on the international border. It was declared a heritage building by both countries in the 1970s and 1980s.

The library has two different addresses and postal codes: 93 Caswell Avenue, Derby Line, Vermont, 05830 and 1 rue Church (Church Street), Stanstead, Quebec, J0B 3E2.