Founded in 1769, Hillsborough County is one of 10 counties in the state of New Hampshire. Historically, Hillsborough County was one of five original counties. The city of Manchester and Nashua is the county seat. With FIPS code of 11, Hillsborough County has a population of 422,937 and area of 876 square miles (2,269 km2).
List of all cities in Hillsborough County, NH alphabetically
| City/Town | Postal Code | Area Code |
| Amherst, NH | 03031 | 603 |
| Antrim, NH | 03440 | 603 |
| Bedford, NH | 03110 | 603 |
| Bennington, NH | 03442 | 603 |
| Brookline, NH | 03033 | 603 |
| Deering, NH | 03244 | 603 |
| Francestown, NH | 03043 | 603 |
| Goffstown, NH | 03045 | 603 |
| Greenfield, NH | 03047 | 603 |
| Greenville, NH | 03048 | 603 |
| Hancock, NH | 03449 | 603 |
| Hillsboro, NH | 03244 | 603 |
| Hillsborough, NH | 03244 | 603 |
| Hollis, NH | 03049 | 603 |
| Hudson, NH | 03051 | 603 |
| Litchfield, NH | 03052 | 603 |
| Lyndeborough, NH | 03082 | 603 |
| Manchester, NH | 03101 | 603 |
| 03102 | 603 | |
| 03103 | 603 | |
| 03104 | 603 | |
| 03105 | 603 | |
| 03107 | 603 | |
| 03108 | 603 | |
| 03109 | 603 | |
| 03110 | 603 | |
| 03111 | 603 | |
| Mason, NH | 03048 | 603 |
| Merrimack, NH | 03054 | 603 |
| Milford, NH | 03055 | 603 |
| Mount Vernon, NH | 03057 | 603 |
| Nashua, NH | 03060 | 603 |
| 03061 | 603 | |
| 03062 | 603 | |
| 03063 | 603 | |
| 03064 | 603 | |
| New Boston, NH | 03070 | 603 |
| New Ipswich, NH | 03071 | 603 |
| Nh Insurance, NH | 03107 | 603 |
| Pelham, NH | 03076 | 603 |
| Peterborough, NH | 03458 | 603 |
| Pinardville, NH | 03102 | 603 |
| Shared Firm Zip, NH | 03111 | 603 |
| Sharon, NH | 03458 | 603 |
| Temple, NH | 03084 | 603 |
| Weare, NH | 03281 | 603 |
| West Peterborough, NH | 03468 | 603 |
| Wilton, NH | 03086 | 603 |
| Windsor, NH | 03244 | 603 |