Bluffton is located in Allen county Ohio with a geographic area of 3.7 square miles. The total population in Bluffton is 4,024 with 47.2% male and 52.8% female. Children under age 5 represent 7.5% of the population, under age 18 equal 22.4% of the population and over age 65 is 21.8% of the population. The median household income is $68,836, per capita income is $31,747. There are a total of 1,537 housing units with 69.8% owner occupied. Education includes 27.8% of residents that are high school graduates and 40.5% with a bachelor's degree or higher. The average temperature in Bluffton in the summer is 73 degrees, and in the winter 32 degrees.