I have a DeLorme Atlas of South Dakota, but Edmunds County is on four pages.
These are the townships, beginning top (north) left (west):
Modena, Hosmer, Sangamon, North Bryant, Adrian, Rosette, Belle, Pembrook
Bowdle, Cottonwood Lake, Glen, Bryant, Huntley, Ipswich, Fountain, Cortlandt
Odessa, Cloyd Valley, Glover, Montpelier, Cleveland, Harmony, Union,Richland
Hudson, Madison, Hillside, Vermont, Liberty, Powell, Kent, Clear Lake