The Mabel K. Richardson Collection is made up of distinct manuscript collections focusing primarily on South Dakota and the surrounding region. These papers include correspondence, photographs, journals, scrapbooks, maps, and other manuscript materials. The Richardson Collection covers a wide variety of subjects but concentrates on the people, places, and events in South Dakota's cultural, political, and economic history.
The papers of many South Dakota elected officials are found in the collection, including governors, state legislators, U.S. Representatives, and U.S. Senators. Highlights include the papers of U.S. Senator James Abourezk (1971-1979), Dakota Territorial Legislator Horace J. Austin, U.S. Senator (1865-1867,1891-1891) and South Dakota Governor Peter Norbeck (1917-1936), U.S. Representative William Williamson (1921-1933), and South Dakota Governor Richard F. Kneip (1971-1978).