Below is a list of Waterloo IL zip codes. For your research we have also included Waterloo Area Code, Time Zone, UTC and the local Monroe County FIPS Code. Each Waterloo Illinois zip code has a center Longitude / Latitude point (the Waterloo center is -90.157203674316 / 38.33219909668). For your convenience we have also indicated if that zip code in Waterloo observes Daylight Savings time.