Winnebago County Illinois is covered by a total of 33 ZIP Codes. There are 13 ZIP Codes in Winnebago County that extend into adjacent counties (Boone County, Ogle County, and Stephenson County). Of the ZIP codes within or partially within Winnebago County there are 22 Standard ZIP Codes and 10 PO Box ZIP Codes.
Click on the ZIP Codes in the interactive map to view more information. The map control in the upper right corner can be used to toggle map layers on and off. The red outline is the border of Winnebago County and can be turned on and off. Each type of postal code can also be turned on and off.