 20.4% of residents were under the age of 18; 9.2% were between the ages of 18 and 24; 20% were from 25 to 44; 30.1% were from 45 to 64; and 20.4% were 65 years of age or older.The gender makeup of the city was 50.5% male and 49.5% female.Matt Ingebretson is the mayor of Thornton.