[4] The rear of the building has been expanded several times over the century to provide additional space for county government.

[5] The exterior of the courthouse consists of gray limestone ashlar walls, which are rusticated on the first story.

The north, west, and south facades feature Ionic columns spanning from the second to the third story.

Two murals painted in 1919 by Franz Biberstein depict romanticized impressions of the area's early fur trading and lumber rafting history.

[4][6] The grounds of the courthouse include a marble war memorial and various commemorative markers related to local history.