Frost line depth in New Hampshire
Estimated frost depth in typical soil runs from 33″ to 53″ across New Hampshire's 10 counties. Pick your county or enter a ZIP code for a local estimate.
Deepest frost
- Coos County 53″
- Carroll County 45″
- Grafton County 41″
- Sullivan County 40″
- Merrimack County 39″
Mildest
Frost depth by county
| County | Est. frost (typical soil) | Typical code range |
|---|---|---|
| Belknap County | 38″ | 30–48″ |
| Carroll County | 45″ | 36–54″ |
| Cheshire County | 38″ | 30–48″ |
| Coos County | 53″ | 42–66″ |
| Grafton County | 41″ | 36–54″ |
| Hillsborough County | 36″ | 30–48″ |
| Merrimack County | 39″ | 36–48″ |
| Rockingham County | 33″ | 30–42″ |
| Strafford County | 35″ | 30–48″ |
| Sullivan County | 40″ | 36–54″ |
Common questions
What is the frost line depth in New Hampshire?
It ranges from about 33 inches in the mildest county to 53 inches in the coldest, in typical soil.
Which New Hampshire county has the deepest frost?
Coos County, at about 53 inches in typical soil.