The historic Washington County Courthouse in Stillwater, Minnesota, United States, is one of the oldest standing courthouses in Minnesota. It was the center of Washington County government for over a century, from the building's completion in 1870 until 1975. It was listed on the National Register of Historic Places in 1971 for having state-level significance in the themes of architecture and government/politics. It was nominated as Minnesota's oldest functioning courthouse and one of its few surviving examples of monumental public architecture from the mid-19th century.