Hillsdale is located in Rock island county Illinois with a geographic area of 0.6 square miles. The total population in Hillsdale is 531 with 53.1% male and 46.9% female. Children under age 5 represent 2.4% of the population, under age 18 equal 19.6% of the population and over age 65 is 16.2% of the population. The median household income is $75,625, per capita income is $26,316. There are a total of 187 housing units with 89.3% owner occupied. Education includes 34.2% of residents that are high school graduates and 7.5% with a bachelor's degree or higher. The average temperature in Hillsdale in the summer is 74 degrees, and in the winter 27 degrees.