Below is a list of Thornton IL zip codes. For your research we have also included Thornton Area Code, Time Zone, UTC and the local Cook County FIPS Code. Each Thornton Illinois zip code has a center Longitude / Latitude point (the Thornton center is -87.616798400879 / 41.56840133667). For your convenience we have also indicated if that zip code in Thornton observes Daylight Savings time.