Sauk City

Sauk City is a village in Sauk County, Wisconsin, United States. The population was 3,410 at the 2010 census. The first incorporated village in the state, the community was founded by Agoston Haraszthy and his business partner, Robert Bryant in the 1840s. The village is adjacent to Prairie du Sac; together, these twin villages are referred to as Sauk Prairie.

Sauk City in "The Fillmore Shoggoth"
At some point in the mid-20th Century, the United States was forced to destroy Sauk City with atomic weapons after shoggoths attacked the town.

Literary comment
Sauk City is the birthplace of August Derleth, author and friend of H.P. Lovecraft. Derleth founded Arkham House publishing after Lovecraft's death to insure Lovecraft's work remained in print. Presumably this connection is why Harry Turtledove felt compelled to destroy such a small and inoffensive village in "The Fillmore Shoggoth".