Below is a list of Williamsville IL zip codes. For your research we have also included Williamsville Area Code, Time Zone, UTC and the local Sangamon County FIPS Code. Each Williamsville Illinois zip code has a center Longitude / Latitude point (the Williamsville center is -89.557998657227 / 39.953899383545). For your convenience we have also indicated if that zip code in Williamsville observes Daylight Savings time.