Gardner is located in Grundy county Illinois with a geographic area of 2.9 square miles. The total population in Gardner is 1,429 with 52.6% male and 47.4% female. Children under age 5 represent 2.8% of the population, under age 18 equal 15.1% of the population and over age 65 is 15.0% of the population. The median household income is $67,441, per capita income is $35,716. There are a total of 569 housing units with 81.5% owner occupied. Education includes 45.2% of residents that are high school graduates and 10.5% with a bachelor's degree or higher. The average temperature in Gardner in the summer is 74 degrees, and in the winter 27 degrees.