Jefferson is located in Union county South dakota with a geographic area of 0.5 square miles. The total population in Jefferson is 677 with 49.9% male and 50.1% female. Children under age 5 represent 2.5% of the population, under age 18 equal 25.7% of the population and over age 65 is 19.1% of the population. The median household income is $55,313, per capita income is $30,765. There are a total of 315 housing units with 84.4% owner occupied. Education includes 31.7% of residents that are high school graduates and 9.8% with a bachelor's degree or higher. The average temperature in Jefferson in the summer is 70 degrees, and in the winter 15 degrees.
