From the record
“Fern School is a historic school in the town of Fern, Wisconsin. The school, located on Wisconsin Highway 101 3 miles (4.8 km) north of County Highway C, was built in 1921 and has also served as the Fern Town Hall.”
Wikipedia article Fern School, CC BY-SA 4.0.
One of 5 National Register listings published here for Florence County · listed in 1981 · category: Building · built in 1921.
Sources: the Wikipedia article · the case file at the National Archives · the National Register database, National Park Service