Couper is well known for his winged figures, such as the Recording Angel in Elmwood Cemetery at the Couper Family plot in Norfolk, and allegorical figures Psyche, and A Crown for the Victor, in the Montclair Art Museum.
Bronze bust of Charles Darwin, created NY 1909 and presented to the American Museum of Natural History. A replica of this piece was also presented to Christ's College, Cambridge where Darwin had been an undergraduate.
Statue of Joseph Bryan, Monroe Park, Richmond, Virginia 1910
^Raynor, Vivien. " Art; THE MAGNET OF MONTCLAIR: ITS ATTRACTIONS ON VIEW", The New York Times, December 27, 1981. Accessed December 6, 2007. "By the 1890s, the colony included several sculptors, among them Jonathan Scott Hartley, Inness's son-in-law, and William Couper. It was Couper who built the substantial villa, Poggioridente, an Italianate pile that still stands on Upper Mountain Avenue."