Vassar is located in Osage county Kansas with a geographic area of 4.9 square miles. The total population in Vassar is 865 with 48.0% male and 52.0% female. Children under age 5 represent 0.8% of the population, under age 18 equal 21.7% of the population and over age 65 is 16.1% of the population. The median household income is $80,313, per capita income is $36,580. There are a total of 326 housing units with 76.4% owner occupied. Education includes 28.5% of residents that are high school graduates and 31.0% with a bachelor's degree or higher. The average temperature in Vassar in the summer is 78 degrees, and in the winter 32 degrees.