Cornelius is located in Washington county Oregon with a geographic area of 2.3 square miles. The total population in Cornelius is 12,767 with 48.9% male and 51.1% female. Children under age 5 represent 5.1% of the population, under age 18 equal 24.2% of the population and over age 65 is 12.6% of the population. The median household income is $72,788, per capita income is $28,883. There are a total of 4,153 housing units with 75.8% owner occupied. Education includes 19.4% of residents that are high school graduates and 22.6% with a bachelor's degree or higher. The average temperature in Cornelius in the summer is 67 degrees, and in the winter 35 degrees.