Duncan is located in Stephens county Oklahoma with a geographic area of 43.0 square miles. The total population in Duncan is 22,529 with 47.9% male and 52.1% female. Children under age 5 represent 6.7% of the population, under age 18 equal 23.7% of the population and over age 65 is 18.0% of the population. The median household income is $50,017, per capita income is $25,983. There are a total of 8,862 housing units with 68.7% owner occupied. Education includes 37.2% of residents that are high school graduates and 22.6% with a bachelor's degree or higher. The average temperature in Duncan in the summer is 80 degrees, and in the winter 42 degrees.
