Merrimack County New Hampshire is covered by a total of 35 ZIP Codes. There are 6 ZIP Codes in Merrimack County that extend into adjacent counties (Belknap County, Hillsborough County, Rockingham County, and Sullivan County). Of the ZIP codes within or partially within Merrimack County there are 29 Standard ZIP Codes, 1 Unique ZIP Codes and 5 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 Merrimack County and can be turned on and off. Each type of postal code can also be turned on and off.