There are several:
VA Medical Center (Hospitals)
Sioux Falls: Sioux Falls VA Health Care System
Fort Meade: VA Black Hills Health Care System - Fort Meade Campus
Hot Springs: VA Black Hills Health Care System - Hot Springs Campus
Community Based Outpatient Clinic
Aberdeen: Aberdeen VA Clinic
Eagle Butte: Eagle Butte VA Clinic
Eagle Butte: Faith VA Clinic
Eagle Butte: Isabel Community Based Outpatient Clinic
McLaughlin: McLaughlin VA Clinic
Mission: Mission CBOC
Pierre: Pierre VA Clinic
Pine Ridge: Pine Ridge VA Clinic
Rapid City: Rapid City VA Clinic
Wagner: Wagner CBOC
Watertown: Watertown CBOC
Winner: Winner VA Clinic
Also, to get a ride to the nearest VA Hospital, or Clinic, you can always call the
Disable American Veterans. You do not have to be disabled, you just have to need a ride. Several times, I've called DAV when the VA sent me to Billings for appointments.