However, on November 3, 1908, it was again created (with altered boundaries) from Butte County's area, and on February 17, 1909 its governing organization was completed.

[4] Custer National Forest has its South Dakota portion in Harding County, and South Dakota State University operates the Antelope Range and Livestock Research Station about 14 miles (23 km) east of Buffalo.

Harding County lies at the northwest corner of South Dakota.

Its highest point is a ridge that runs northwest to southeast near the county's southwest corner, at 3,366 ft (1,026 m) ASL.

Harding is a heavily Republican county in Presidential and Congressional elections.

Jimmy Carter in 1976 almost carried the county, but since then the solitary Democrat to top 22 percent of Harding County's ballots has been Michael Dukakis in the drought-influenced 1988 election – and none of the last seven Democratic presidential candidates have topped so much as twenty percent.

In the State House Harding is part of district 28B, which is held by Republican J. Sam Marty.