Dahlgren is located in Hamilton county Illinois with a geographic area of 1.0 square miles. The total population in Dahlgren is 699 with 47.4% male and 52.6% female. Children under age 5 represent 10.0% of the population, under age 18 equal 29.8% of the population and over age 65 is 23.6% of the population. The median household income is $50,038, per capita income is $20,706. There are a total of 273 housing units with 80.2% owner occupied. Education includes 34.8% of residents that are high school graduates and 12.5% with a bachelor's degree or higher. The average temperature in Dahlgren in the summer is 74 degrees, and in the winter 27 degrees.