Trehörningen is Swedish for "The Triangle", or literally "The Three-Corner", and can refer to many different geographical locations, including: Trehörningen (Sjödalen) - a lake in Huddinge Municipality, in the Sjödalen-Fullersta area. Trehörningen, Hanveden - a lake in Huddinge Municipality, in the Hanveden area. Trehörningen, Tyresta - a lake in Tyresö Municipality, in Tyresta National Park
See also Trekanten (disambiguation) ("The Three-Edge")