Keystone is a town in the Black Hills region of Pennington County, South Dakota, United States. The population was 337 at the 2010 census. It had its origins in 1883 as a mining town, and has since transformed itself into a resort town, serving the needs of the millions of visitors to the Mount Rushmore National Memorial, which is located just beyond city limits. Keystone was heavily damaged in the 1972 Black Hills flood.
Keystone, South Dakota
Town
Business district in Keystone
Motto(s):
"Home Of Mount Rushmore"
Location in Pennington County and the state of South Dakota
Coordinates: 43°53′37″N 103°25′34″WCountryUnited StatesStateSouth DakotaCountyPenningtonArea
[1]
• Total2.86 sq mi (7.41 km2) • Land2.86 sq mi (7.41 km2) • Water0 sq mi (0 km2)Elevation
4,331 ft (1,320 m)Population
(2010)[2]
• Total337 • Estimate
(2012[3])
342 • Density117.8/sq mi (45.5/km2)Time zoneUTC-7 (Mountain (MST)) • Summer (DST)UTC-6 (MDT)ZIP code
57751
Area code(s)605FIPS code46-33820[4]GNIS feature ID1261912[5]
The town took its name from a local mine, which most likely was named after the keystone Masonic symbol.