Armstrong County was disorganized in 1952, the last US county to cease to exist. The 1920 population was 52, and that had dwindled to 23 by the time of its disestablishment.It now constitutes the southern part of Dewey County. There are a few roads in the area. Th easiest way to visit the historical Armstrong County is by turning south from US 212,, between Parade and Ridgeview SD, where there is a black-top road. This road goes about 3 miles into Armstrong County, and then another few miles, where it connects with a Cheyenne Reservation road, unpaved, leading east and west.If the area has any permanant residents, they are probably very few, and probably invisible to a visitor.The area of the original county was about 200 square miles, but some 10% of that is now under water, owing to the subsequent creation of Lake Oahe.
REMAINS: Probably none.