New Hampshire counties by area
Official, comparable measurements for 10 counties and county equivalents.
- 367.5–401.9 mi²
- 537.9–695.6 mi²
- 706.7–876.5 mi²
- 931.9–932.9 mi²
- 1,708.6–1,794.6 mi²
- 17–55 per mi²
- 57–82 per mi²
- 111–162 per mi²
- 169–367 per mi²
- 466–494 per mi²
Understanding New Hampshire’s county areas
The land-area range runs from Strafford County at 367.5 mi² to Coos County at 1,794.6 mi². The largest has 4.9 times the land area of the smallest and accounts for 20% of the combined county land in New Hampshire. Compare with every state’s largest county.
The median county-equivalent land area is 791.6 mi², above the national median of 604.5 mi². The median describes the middle of the county size distribution; it does not describe how people or development are distributed. A state with a few very large counties can have a much smaller median than its largest entry suggests.
Where water changes the picture
Rockingham County has the most assigned water area, at 99.7 mi². Belknap County has the highest water share, with water making up 14.5% of its total area. Water area and water percentage answer different questions: the first measures an amount, while the second measures the mix of land and water.
Across all 10 entries, water accounts for 4.2% of the combined total area. This is calculated from the summed land and water measurements, rather than averaging county percentages, which would give each small and large county equal weight.
Where people live
An estimated 1,415,342 people lived in New Hampshire on July 1, 2025 (+2.7% since 2020), or 0.4% of the national total in this dataset. Hillsborough County is the most populous county equivalent, with 433,415 residents — 30.6% of the state. The largest by land, Coos County, has 31,343.
Across the state there are 158 people per square mile of land. County densities range from 494 in Hillsborough County to 17 in Coos County; the median county equivalent has 136. Switch the map above to density to see where the state’s population concentrates.
Compare the largest and smallest county equivalents in New Hampshire to see land, water, and total area on the same scale.
These calculations use the 2026 Census county records listed below. County-equivalent boundaries vary between states; area alone does not measure population, density, or usable land. See coverage and calculation rules.
Complete area table
Sorted from largest to smallest land area.
| # | County / equivalent | Land | Water | Water share | Population | Per mi² |
|---|---|---|---|---|---|---|
| 1 | Coos CountyGEOID 33007 | 1,794.6 mi² | 35.7 mi² | 2% | 31,343 | 17 |
| 2 | Grafton CountyGEOID 33009 | 1,708.6 mi² | 41.1 mi² | 2.3% | 93,225 | 55 |
| 3 | Merrimack CountyGEOID 33013 | 932.9 mi² | 22.1 mi² | 2.3% | 158,078 | 169 |
| 4 | Carroll CountyGEOID 33003 | 931.9 mi² | 61.6 mi² | 6.2% | 52,784 | 57 |
| 5 | Hillsborough CountyGEOID 33011 | 876.5 mi² | 16 mi² | 1.8% | 433,415 | 494 |
| 6 | Cheshire CountyGEOID 33005 | 706.7 mi² | 22.2 mi² | 3% | 78,269 | 111 |
| 7 | Rockingham CountyGEOID 33015 | 695.6 mi² | 99.7 mi² | 12.5% | 324,077 | 466 |
| 8 | Sullivan CountyGEOID 33019 | 537.9 mi² | 14.3 mi² | 2.6% | 43,961 | 82 |
| 9 | Belknap CountyGEOID 33001 | 401.9 mi² | 68.1 mi² | 14.5% | 65,147 | 162 |
| 10 | Strafford CountyGEOID 33017 | 367.5 mi² | 15.1 mi² | 3.9% | 135,043 | 367 |