1940 United States Congressional Elections – South Dakota

United States House of Representatives – District 1 – GOP Hold

Karl E. Mundt (R-inc) – 135,406 – 59.55%

Oscar Fosheim (D) – 91,967 – 40.45%

Total Votes – 227,373 – 100.00%

United States House of Representatives – District 2 – GOP Hold

Francis H. Case (R-inc) – 47,051 – 66.10%

Arthur W. Watwood (D) – 24,127 – 33.90%

Total Votes – 71,178 – 100.00%

Source: Office of the Clerk of the United States House of Representatives