The Sihlsee sits just southeast of town, an artificial reservoir created in 1937 by damming the Sihl river. At about five kilometres long it is the largest lake in the canton of Schwyz, and in summer it functions as the local beach: swimming spots along the shore, sailing and windsurfing, and a campsite at the eastern end near Euthal.
The water is cold even in August — this is a mountain reservoir at 890 metres — but on a clear summer day the setting is hard to fault: green hills, the Mythen peaks visible to the north, and very few tourists. A path circles the whole lake, roughly 18 kilometres, which makes a pleasant half-day walk.