Keystone is located in west South Dakota. Keystone is part of Pennington County. Keystone has 2.86 square miles of land area and has no water area. As of 2010-2014, the total Keystone population is 365, which has grown 17.36% since 2000. The population growth rate is much higher than the state average rate of 10.58% and is much higher than the national average rate of 11.61%. Keystone median household income is $34,375 in 2010-2014 and has grown by 30.18% since 2000. The income growth rate is lower than the state average rate of 42.67% and is higher than the national average rate of 27.36%. Keystone median house value is $131,300 in 2010-2014 and has grown by 43.50% since 2000. The house value growth rate is much lower than the state average rate of 70.48% and is lower than the national average rate of 46.91%. As a reference, the national Consumer Price Index (CPI) inflation rate for the same period is 26.63%. On average, the public school district that covers Keystone is much better than the state average in quality. The Keystone area code is 605.