Marathon is located in Buena vista county Iowa with a geographic area of 0.7 square miles. The total population in Marathon is 183 with 46.4% male and 53.6% female. Children under age 5 represent 0.5% of the population, under age 18 equal 16.9% of the population and over age 65 is 21.3% of the population. The median household income is $43,750, per capita income is $36,765. There are a total of 83 housing units with 83.1% owner occupied. Education includes 51.8% of residents that are high school graduates and 12.0% with a bachelor's degree or higher. The average temperature in Marathon in the summer is 71 degrees, and in the winter 23 degrees.