Middlesex County Massachusetts is covered by a total of 110 ZIP Codes. There are 3 ZIP Codes in Middlesex County that extend into adjacent counties (Norfolk County, and Worcester County). Of the ZIP codes within or partially within Middlesex County there are 82 Standard ZIP Codes, 7 Unique ZIP Codes and 20 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 Middlesex County and can be turned on and off. Each type of postal code can also be turned on and off.