South Dakota State Geologists

J.E. Todd - State Geologist from 1893 - 1903

Ellwood C. Perisho - State Geologist from 1903 - 1914

Freeman Ward - State Geologist from 1915 - 1926

E. P. Rothrock - State Geologist from 1926 - 1957

Allen F. Agnew - State Geologist from 1957 - 1963

Duncan J. McGregor - State Geologist from 1963 - 1978

Merlin J. Tipton - State Geologist from 1978 - 1992

Cleo M. Christensen - State Geologist from 1992 - 1997

Derric L. Iles - State Geologist from 1997 - 2018