The Karl Mundt Collection contains materials that represent the breadth of Senator Mundt's life and career. The approximate period of time covered by these materials is from Mundt's birth in 1900, to the death of his wife, Mary Moses, in 1985. In addition to Mundt's Congressional papers, the collection includes personal effects, family heirlooms, a reference library, and various other ephemera and memorabilia related to the Senator and the impact of his work.

The document collection is arranged into fifteen distinct records groups, and further divided into series and sub-series that reflect specific topics and subjects that are addressed by the materials in those series. In total the Karl Mundt Collection includes over 1,500 document boxes totaling nearly 700 linear feet, containing approximately two million individual documents. The media collection consists of over 300 audiovisual recordings, 6,000 photographs, paintings, and 100 scrapbooks. In addition to those materials, the collection holds approximately 270 three-dimensional artifacts, and over 1,200 bound volumes.