Lake Sempach
Sempachersee
Lake Sempach Show map of Canton of Lucerne Lake Sempach Show map of Switzerland Lake Sempach Show map of Alps
Location	Canton of Lucerne
Coordinates	47°8.6667′N 8°9.1′E / 47.1444450°N 8.1517°E / 47.1444450; 8.1517
Primary inflows	Gross Aa, Chli Aa (Sempachersee), Meierhofbach, Wilibach, Dorfbach (Sempachersee), Brandbach, Röllbach (Sempachersee), Lipperütibach, and some unnamed
Primary outflows	Suhre
Basin countries	Switzerland
Surface area	14.5 km2 (5.6 sq mi)
Average depth	44 m (144 ft)
Max. depth	87 m (285 ft)
Water volume	0.66 km3 (540,000 acre⋅ft)
Residence time	16.9 years
Surface elevation	503.77 m (1,652.8 ft)
Islands	Gamma Insel
Settlements	Sursee, Sempach

Lake Sempach (German: Sempachersee) is a lake in the canton of Lucerne, Switzerland. Its area is about 14.5 km² (5.6 sq mi) and its maximum depth is 87 m (285 ft).

A 50-metre-large (160 ft) island named Gamma Insel is located east of Sursee.

In the 17th century the lake counted with five ferries, that brought goods to the weekly market in Sursee.^[1]

Many inhabitants of local areas swim, boat, paddle, and fish in Lake Sempach, due to its ease of accessibility.

• Media related to Lake Sempach at Wikimedia Commons
• Sempachersee Archived 2007-09-27 at the Wayback Machine (in German)
• http://www.sempachersee.ch (in German) Information about the municipalities on the lake
• Waterlevels Lake Sempach at Sempach