Petersburg is located in Menard county Illinois with a geographic area of 1.6 square miles. The total population in Petersburg is 2,564 with 49.8% male and 50.2% female. Children under age 5 represent 5.9% of the population, under age 18 equal 21.5% of the population and over age 65 is 16.8% of the population. The median household income is $62,574, per capita income is $43,622. There are a total of 1,119 housing units with 62.4% owner occupied. Education includes 30.2% of residents that are high school graduates and 30.0% with a bachelor's degree or higher. The average temperature in Petersburg in the summer is 74 degrees, and in the winter 27 degrees.
