Harmonia Hall, built in 1890, was the meeting place for the members of the Harmonie Gesellschaft. These people were Freethinkers who gathered for intellectual and social purposes. The members were immigrants from Germany and Switzerland or the children of these immigrants. The hall they built was used for meetings and for entertainment and social events. The carpenter who built, and likely designed, Harmonia Hall was Joseph Schafer of Arcadia, Wisconsin.

The Waumandee Freethinkers organized as the Harmonie Gesellschaft (Society) as early as 1861. Among these organizers were John Ochsner and his brother-in-law Henry Waelty. Ochsner and Waelty were Swiss immigrants who first lived in Sauk County, the home of a large Freethinker Society. Society members met the first Sunday of each month for entertainment and for the discussion of important topics of local, political and general importance and interest. Another outgrowth of the group was the Harmonie Singing Society.

While the Harmonie Gesellschaft did not officially dissolve until the 1950s, by the 1930s its numbers had diminished and the group was again meeting in private homes rather than the hall. The Hall is currently owned by the Township and the hall and grounds are used for meetings and special events.