Consists of letters from the Clason family of Cascade Township, Olmsted County, Minnesota. Includes letters written by family members serving in Union Army during the American Civil War, family correspondence from the late 19th century and miscellaneous documents from the early 1900s. The bulk of the letters focus on the military activities of the Clason brothers (William, Isaac and Rufus) and Chancey Rounds, the husband of Betsy Clason. Among the postwar documents are seven letters from Louisa Clason to Betsey Rounds, a pension certificate for Hannah A. Adams and ephemeral items from the Minnesota Soldiers Home and Woman's Relief Corp of the Grand Army of the Republic.