Cook County Illinois is covered by a total of 225 ZIP Codes. There are 19 ZIP Codes in Cook County that extend into adjacent counties (DuPage County, Kane County, Lake County, Mchenry County, and Will County). Of the ZIP codes within or partially within Cook County there are 174 Standard ZIP Codes, 26 Unique ZIP Codes and 25 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 Cook County and can be turned on and off. Each type of postal code can also be turned on and off.