Campbell County History 

French fur traders probably visited what is now Campbell County before Lewis and Clark camped at the mouth of Spring Creek on their way up the Missouri River in 1805. The first settlement was established by Andrew Marsh in 1864, along the Missouri River a few miles north of the mouth of Spring Creek. This settlement was known as Vanderbilt.
 
Campbell County was established by an act of the 1873 Dakota Territory Legislature and was formally organized in 1884, at which time the settlement of LeGrace was selected as the first county seat. In 1888, the county seat was moved to Mound City.
 
A steady settlement of the county began in 1884, when the preemption, homestead, and timber cutline laws were passed. The extension of the railroad into the county in 1901 brought another large influx of settlers. The towns of Artas, Herreid, and Pollock were established along the railroad and soon became the main trading and shipping centers for the area.
 
The population of the county increased steadily until 1930, when it reached a high of 5,629. It began to decline during the drouth and depression years of the 1930's. It declined to 3,531 by 1960 and 2,866 by 1970. The major towns are Herreid, Pollock, Mound City, and Artas. The pioneer towns of LeGrace and Vanderbilt remain as only historic sites.
 

Source:

Soil Survey of Campbell County, South Dakota
United States Department of Agriculture Soil Conservation Service
in cooperation with South Dakota Agricultural Experiment Station
By Thomas M. Schumacher and Kenneth J. Heil, Soil Conservation Service
 
Circa 1895