Below is a list of Grayslake IL zip codes. For your research we have also included Grayslake Area Code, Time Zone, UTC and the local Lake County FIPS Code. Each Grayslake Illinois zip code has a center Longitude / Latitude point (the Grayslake center is -88.033203125 / 42.344898223877). For your convenience we have also indicated if that zip code in Grayslake observes Daylight Savings time.