Williamson county is located in Texas with a geographic area of 1,134.7 square miles. The total population in Williamson county is 570,437 with 49.3% male and 50.7% female. Children under age 5 represent 6.4% of the population, under age 18 equal 25.6% of the population and over age 65 is 12.2% of the population. The median household income is $90,834, per capita income is $38,494. There are a total of 188,113 housing units with 68.2% owner occupied. Education includes 15.1% of residents that are high school graduates and 47.5% with a bachelor's degree or higher. The average temperature in Williamson county in the summer is 83 degrees, and in the winter 51 degrees.