Lake Zürich (Swiss German/Alemannic: Zürisee; German: Zürichsee)[1] is a lake in Switzerland, extending southeast of the city of Zürich. Depending on the context, Lake Zürich or Zürichsee can be used to describe the lake as a whole, or just that part of the lake downstream of the Seedamm at Rapperswil, whilst the part upstream of Rapperswil may be called the Obersee or Upper Lake.