County facts · Land area · October 22, 2026
Largest Counties in New Hampshire by Area and Population
The largest New Hampshire counties by land area and by 2023 population, plus the smallest, county seats and a link to each official parcel map.
Looking for the largest counties in New Hampshire? New Hampshire has 10 counties covering about 8,954 square miles of land, based on the Census Bureau's 2020 Gazetteer. The largest by land area is Coos County, at about 1,795 square miles, roughly 4.9 times the size of the smallest, Strafford County (367 sq mi). Measured by people instead, the largest is Hillsborough County, with about 427,354 residents in the Census Bureau's July 1, 2023 estimate.
Each table below links the county's Platbookmapper page and its official parcel viewer, so you can go straight from the numbers to the property lines.
New Hampshire counties at a glance
- Counties: 10
- Land area: about 8,954 sq mi, plus about 396 sq mi of water inside county lines
- Residents, 2023 estimates: about 1,402,054, or about 157 people per square mile of land
- Median county land area: about 792 sq mi
- With a verified public parcel viewer in our directory: 10 of 10 (10 of them through a statewide viewer)
Every county in New Hampshire points to the same statewide viewer in our directory, the NHDOT Parcel Mosaic Viewer, so one search box covers the whole state and the parcel pop-ups look the same on both sides of a county line.
All 10 New Hampshire counties ranked by land area
| # | County | Seat | Land (sq mi) | Water (sq mi) | 2023 pop. | People per sq mi | Parcel viewer |
|---|---|---|---|---|---|---|---|
| 1 | Coos County | Lancaster | 1,795 | 36 | 31,372 | 17 | NHDOT Parcel Mosaic Viewer |
| 2 | Grafton County | Haverhill | 1,709 | 41 | 93,146 | 55 | NHDOT Parcel Mosaic Viewer |
| 3 | Merrimack County | Concord | 933 | 22 | 157,103 | 168 | NHDOT Parcel Mosaic Viewer |
| 4 | Carroll County | Ossipee | 932 | 62 | 52,448 | 56 | NHDOT Parcel Mosaic Viewer |
| 5 | Hillsborough County | Manchester, Nashua | 877 | 16 | 427,354 | 488 | NHDOT Parcel Mosaic Viewer |
| 6 | Cheshire County | Keene | 707 | 22 | 77,703 | 110 | NHDOT Parcel Mosaic Viewer |
| 7 | Rockingham County | Brentwood | 695 | 100 | 320,689 | 461 | NHDOT Parcel Mosaic Viewer |
| 8 | Sullivan County | Newport | 538 | 14 | 43,969 | 82 | NHDOT Parcel Mosaic Viewer |
| 9 | Belknap County | Laconia | 402 | 68 | 65,027 | 162 | NHDOT Parcel Mosaic Viewer |
| 10 | Strafford County | Dover | 367 | 15 | 133,243 | 363 | NHDOT Parcel Mosaic Viewer |
All 10 ranked by population
- Hillsborough County: about 427,354 residents (30% of the state)
- Rockingham County: about 320,689 residents (23% of the state)
- Merrimack County: about 157,103 residents (11% of the state)
- Strafford County: about 133,243 residents (10% of the state)
- Grafton County: about 93,146 residents (7% of the state)
- Cheshire County: about 77,703 residents (6% of the state)
- Belknap County: about 65,027 residents (5% of the state)
- Carroll County: about 52,448 residents (4% of the state)
- Sullivan County: about 43,969 residents (3% of the state)
- Coos County: about 31,372 residents (2% of the state)
Most and least crowded
- Most people per square mile: Hillsborough County, about 488 (then Rockingham County, 461, and Strafford County, 363)
- Fewest people per square mile: Coos County, about 17 (then Grafton County, 55, and Carroll County, 56)
Counties with the most water
The Census Bureau reports water separately from land. It counts lakes, reservoirs, rivers and, along a coast or a Great Lake, the water inside the boundary.
- Rockingham County: about 100 sq mi of water, 13% of its total area
- Belknap County: about 68 sq mi of water, 15% of its total area
- Carroll County: about 62 sq mi of water, 6% of its total area
Using these numbers in a land search
- Land area is not parcel count. A large rural county can hold fewer parcels than a small suburban one, so size alone says little about how busy its parcel map is.
- Search, don't scroll. In a big county, type an address, owner name or parcel number into the viewer's search box, where it has one, instead of panning across the map.
- Records follow the county line. Deeds, plats and tax bills are kept by the county where the parcel sits, so a tract that crosses a county line usually has a parcel number on each side.
- Rounded figures. Land and water areas are rounded to whole square miles (one decimal for very small places). People per square mile is the 2023 estimate divided by land area.
Related guides
- New Hampshire landowner maps for hunting
- Largest county in each state
- Largest counties in the US by land area
More: All New Hampshire counties on Platbookmapper
Sources
- U.S. Census Bureau Gazetteer files, 2020 county land and water area.
- U.S. Census Bureau, Population Estimates Program, county totals, Vintage 2023 (July 1, 2023 estimates)
- Platbookmapper county GIS directory (live data file behind our county pages, pulled October 22, 2026) for each official parcel viewer.
- County seats: Wikidata (county seat property), cross-checked against Census place names.