Please answer the following question: Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Mahaska County Courthouse -  The Mahaska County Courthouse in Oskaloosa Iowa United States was built in 1886. It was listed on the National Register of Historic Places in 1981 as a part of the County Courthouses in Iowa Thematic Resource. The courthouse is the second building the county has used for court functions and county administration.
Answer:
Building