Hörnli mountain is located on the territory of the community of Fischenthal, in the Zürcher Oberland, in the eastern part of canton of Zürich, in Switzerland. It is 1,133 meters (3,717 ft) high. North of the Hörnli, the Dreiländerstein, altitude 992 meters (3,255 ft), marks the meeting of the boundaries of the three Cantons of Zürich, St.Gallen and Thurgau.