Below is a list of Somonauk IL zip codes. For your research we have also included Somonauk Area Code, Time Zone, UTC and the local Dekalb County FIPS Code. Each Somonauk Illinois zip code has a center Longitude / Latitude point (the Somonauk center is -88.679901123047 / 41.633800506592). For your convenience we have also indicated if that zip code in Somonauk observes Daylight Savings time.