Bad Karlshafen (German: [baːt kaʁlsˈhaːfn̩] ⓘ) is a baroque, thermal salt spa town in the district of Kassel, in Hesse, Germany.

Charles I, Landgrave of Hesse-Kassel, had ambitious plans for town-planning and developing new water trade channels in the region; including a 'haven' in Karlshafen.

Together with his engineer and architect Friedrich Conradi he developed plans for a Landgrave-Carl-Canal in order to avoid customs duty at Hannoversch Münden, but these were never finalised.

Plans for Bad Karlshafen, however, were partially completed in a baroque style by architect Paul du Ry in 1717 and the town was renamed as Carlshaven.

Following the Revocation of the Edict of Nantes in France in 1685, the Kingdom of Savoy-Piedmont-Sardinia followed suit along with their ally and banished it's Waldensian population, during which time, many of these diasporic Northern Italians existed in "ghettoized" ethnic enclaves in Hesse Cassel.