Rock island is located in Colorado county Texas with a geographic area of 5.0 square miles. The total population in Rock island is 447 with 57.5% male and 42.5% female. Children under age 5 represent 6.3% of the population, under age 18 equal 23.3% of the population and over age 65 is 11.6% of the population. The median household income is $42,422, per capita income is $21,151. There are a total of 181 housing units with 82.9% owner occupied. Education includes 40.3% of residents that are high school graduates and 2.2% with a bachelor's degree or higher. The average temperature in Rock island in the summer is 83 degrees, and in the winter 49 degrees.
