Keystone is located in Benton county Iowa with a geographic area of 0.4 square miles. The total population in Keystone is 605 with 44.1% male and 55.9% female. Children under age 5 represent 4.0% of the population, under age 18 equal 21.2% of the population and over age 65 is 27.3% of the population. The median household income is $56,250, per capita income is $26,448. There are a total of 259 housing units with 68.7% owner occupied. Education includes 44.4% of residents that are high school graduates and 18.5% with a bachelor's degree or higher. The average temperature in Keystone in the summer is 72 degrees, and in the winter 23 degrees.
