Lake Lucerne is a lake in central Switzerland and the fourth largest in the country.
The lake has a total area of 114 km² (44 sq mi), an elevation of 434 m (1,424 ft), and a maximum depth of 214 m (702 ft). Its volume is 11.8 km³.
The Reuss River enters the lake at Flüelen (in the canton of Uri, the part called Urnersee) and exits at Lucerne. The lake also receives the Muota (at Brunnen) Engelberger Aa (at Buochs), the Sarner Aa (at Alpnachstad).