Abstract: Papers, 1875-1931, of Nils Pederson Haugen, a Republican congressman from Wisconsin's Tenth District, 1887-1895, and state tax commissioner, 1901-1921. Papers from the years of Haugen's congressional service consist of correspondence with constituents, principally in regard to patronage and pension claims, but also touch upon other matters, including Scandinavian politics and newspapers, local affairs in Pierce County and Superior, and state campaigns, including his own for the gubernatorial nomination in 1894 and that of Robert M. La Follette in 1896. Papers from the years of Haugen's work as tax commissioner touch upon the income tax law of 1911, and include correspondence from 1919-1920 with officials of the National Tax Association, of which Haugen was then president. Papers also include material on Montana state politics from 1921 to 1923, when Haugen served as advisor to the board of equalization of Montana on revision of the state tax laws.