Lake Winnebago is the largest freshwater lake in Wisconsin and spans over 137,000 acres. Historically, it was used as a transportation route by Native Americans and later by Europeans for fur trade. The lake is fed by various rivers and tributaries, including the Fox River, which flows into the lake from the north. The lake's hydrology is influenced by the flow from these tributaries and the amount of snowpack in the surrounding area. The lake is an important source of water for agricultural irrigation and is also used for recreational activities such as fishing, boating, and swimming. The lake hosts various fishing tournaments, including the sturgeon spearing season in February. Overall, Lake Winnebago plays a significant role in the economy and culture of Oshkosh and the surrounding areas.