Milbank is a city in Grant County, South Dakota, along the South Fork of the Whetstone River. The population was 3,640 at the 2000 census. It is the county seat of Grant County. In 1925 The American Legion Department of South Dakota established a new program for high school aged youth that grew into a national program. Milbank is the birthplace of American Legion Baseball played in all fifty states by more than five thousand teams.