Open from Memorial Day to Labor Day, the Old Jail Museum is one of the oldest buildings in continuous use in Sanders County. Originally operating as the county jail, sheriff's office and sheriff's residence, the building now serves the citizens as a museum and focus on preserving Sanders County history, historical artifacts, images and maps.

The displays depict historic eras of Thompson Falls' early development. There are many photographs taken from original glass negatives that give a glimpse into the past of the people, places and events when Sanders County was new. Mining, logging, farming and ranching are shown in stark reality captured by the well-known photographer E.J. Frazier.