Irmo is located in Richland county South carolina with a geographic area of 6.9 square miles. The total population in Irmo is 12,397 with 45.1% male and 54.9% female. Children under age 5 represent 4.3% of the population, under age 18 equal 20.6% of the population and over age 65 is 15.9% of the population. The median household income is $75,344, per capita income is $35,643. There are a total of 4,827 housing units with 81.9% owner occupied. Education includes 14.8% of residents that are high school graduates and 43.1% with a bachelor's degree or higher. The average temperature in Irmo in the summer is 77 degrees, and in the winter 43 degrees.