Mariemont is located in Hamilton county Ohio with a geographic area of 0.9 square miles. The total population in Mariemont is 3,445 with 48.9% male and 51.1% female. Children under age 5 represent 6.0% of the population, under age 18 equal 26.8% of the population and over age 65 is 15.0% of the population. The median household income is $104,828, per capita income is $59,117. There are a total of 1,413 housing units with 68.2% owner occupied. Education includes 2.6% of residents that are high school graduates and 80.7% with a bachelor's degree or higher. The average temperature in Mariemont in the summer is 73 degrees, and in the winter 32 degrees.