Penobscot County Maine is covered by a total of 52 ZIP Codes. There are 13 ZIP Codes in Penobscot County that extend into adjacent counties (Aroostook County, Hancock County, Piscataquis County, Somerset County, and Washington County). Of the ZIP codes within or partially within Penobscot County there are 48 Standard ZIP Codes, 1 Unique ZIP Codes and 3 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 Penobscot County and can be turned on and off. Each type of postal code can also be turned on and off.