Duncan is located in Platte county Nebraska with a geographic area of 0.5 square miles. The total population in Duncan is 487 with 55.2% male and 44.8% female. Children under age 5 represent 8.8% of the population, under age 18 equal 18.5% of the population and over age 65 is 40.5% of the population. The median household income is $38,542, per capita income is $27,174. There are a total of 213 housing units with 91.5% owner occupied. Education includes 31.9% of residents that are high school graduates and 21.1% with a bachelor's degree or higher. The average temperature in Duncan in the summer is 72 degrees, and in the winter 26 degrees.