The original courthouse built on this site in 1887 included a jail and sheriff's residence and served a population of about 2,000 people. As a logging town, Aitkin became a railhead and an important stopping point for boats on the Mississippi River. By 1910, the population had grown extensively, making the courthouse facilities inadequate. To free space, a separate jail was constructed in 1915. The two-story red brick building, designed by Minneapolis architect E.C. Pell and located immediately west of the courthouse, included a nine-room sheriff's residence, presently used for office space, and a cell block extending to the rear. In 1920, Aitkin County established a building fund for a new courthouse and hired the St. Paul architectural firm Tolz, King, & Day to design it. Officials decided not to issue bonds, delaying construction until 1929. The stone and brick courthouse is a well-preserved example of the Beaux Arts Classicism style prevalent in the 1920s, with a flat roof concealed by a parapet, marble wainscoting, terrazzo floors, oak woodwork, and a stained glass skylight in the court chamber. The interiors and exteriors of these buildings retain a significant degree of historical integrity.