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New Hampshire soil by county

Across New Hampshire's mapped land, shrink-swell clay limits houses without basements on 2% and a shallow water table limits basements on 39%.

Highest clay shares: Cheshire County (4%), Hillsborough County (3%), Merrimack County (2%), Belknap County (2%), Carroll County (2%). Highest water-table shares: Coos County (53%), Merrimack County (49%), Rockingham County (48%), Belknap County (42%), Strafford County (39%).

Data as of September 22, 2026 · 10 counties

Belknap County: 2%Carroll County: 2%Cheshire County: 4%Coos County: 0%Grafton County: 1%Hillsborough County: 3%Merrimack County: 2%Rockingham County: 0%Strafford County: 1%Sullivan County: 2%
Expansive clay: share of mapped land where shrink-swell clay limits houses without basementsunder 10%10-25%25-40%40-60%60%+
Belknap County: 42%Carroll County: 36%Cheshire County: 27%Coos County: 53%Grafton County: 29%Hillsborough County: 28%Merrimack County: 49%Rockingham County: 48%Strafford County: 39%Sullivan County: 26%
High water table: share of mapped land where a shallow water table limits basementsunder 10%10-25%25-40%40-60%60%+

Every county in New Hampshire

Select a column heading to sort.
Belknap County 2% 42% 86% 0 1979
Carroll County 2% 36% 100% 47 1982
Cheshire County 4% 27% 0% 20 1972
Coos County under 1% 53% 47% 17 1969
Grafton County 1% 29% 71% 57 1981
Hillsborough County 3% 28% 7% 38 1978
Merrimack County 2% 49% 31% 11 1977
Rockingham County under 1% 48% 100% 479 1983
Strafford County 1% 39% 100% 7 1979
Sullivan County 2% 26% 0% 18 1974

How these shares are counted

Shares are of mapped land in USDA's soil survey (SSURGO), weighted by each soil's share of every map unit. Drought is the US Drought Monitor's D1-or-worse share on the September 22, 2026 map. Flood losses are FEMA NFIP records since 2016. Sources and methods.