Grafton County: Jasper Rockhounding in Grafton County, New Hampshire

Quick details

Access

Public area

County

Grafton County

State

New Hampshire

Nearest road

Main Street

Coordinates

44.26846, -71.60743

Geology at Grafton County

This spot sits on Biotite granite, mapped as granite that formed roughly 460 to 445 million years ago. Plutonic rock like this weathers slowly into grus and boulders, and the most productive collecting is typically in weathered zones and drainages.

Mapped unit

Biotite granite

Age

460–445 Ma (Late Ordovician)

Rock types

granite

Elevation

1,260 ft

Geologic mapping via Macrostrat and the underlying state geological survey maps (CC BY 4.0). Bedrock at the surface can vary within a mapped unit.

Best time to visit Grafton County

Best months: April to October. Typical highs run 80°F in midsummer and 28°F in midwinter, with winter lows near 3°F.

Climate normals: NOAA 1991-2020 monthlies, BETHLEHEM 2 station (4 mi away).

Land & collecting status

Generally open to casual rockhounding

Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig.

Public-land rules vary by agency, season, and field office. The RockHoundR app pulls live BLM, USFS, NPS, and tribal overlays so you can see exactly which agency manages the ground at this spot.

Sources & verification

Spot details combine the public RockHoundR location dataset, normalized mineral labels, agency land-status checks in the app, and community submissions. Coordinates are approximate until verified in the field.

Sources: RockHoundR public spot dataset, app land overlays, and local agency review before each trip.

Found at Grafton County

Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

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