Lake Winnebago is the largest lake in Wisconsin. It measures 557 km² (215 sq miles) and it is fed and drained by the Fox River. The lake is part of an all-water route between the Great Lakes and the Mississippi River. The two most important towns on Lake Winnebago are Oshkosh and Fond du Lac. The lake and its surroundings are a major recreation area.

Accommodation and restaurants are available in many places around the lake. Lake Winnebago is in the east of Wisconsin, 110 km northeast from Madison and 1100 km northwest from Washington D.C.