Best spot

Tunnel Brook: Gold Prospecting in Grafton County, New Hampshire

Updated July 2026

Tunnel Brook is a long-favored gold-panning stream in the White Mountain National Forest, and coarse gold with the occasional small nugget has turned up in its gravels where it drops over fractured bedrock. It flows into the Wild Ammonoosuc near Route 112 in the heart of New Hampshire's historic gold district. A free Forest Service permit covers panning here. Reported finds include gold placer, gold nugget. Below: coordinates, access notes, nearby spots, and trip-planning links.

Tunnel Brook photos

Public image records connected to this spot or its reported material.

1 photo

White Mountain National Forest near Benton, New Hampshire, where Tunnel Brook flows

Quick details

Access: Public area
County: Grafton County
State: New Hampshire
Nearest road: Tunnel Brook Road
Coordinates: 44.09300, -71.90000

Geology at Tunnel Brook

This spot sits on Ammonoosuc Volcanics, Bimodal volcanic rocks, mapped as felsic volcanic and mafic volcanic that formed roughly 470 to 445 million years ago. Gold in volcanic terrain like this is usually tied to old vein systems and the gravels that drain them, so nearby washes tend to carry the color.

Mapped unit: Ammonoosuc Volcanics, Bimodal volcanic rocks
Age: 470–445 Ma (Middle Ordovician to Late Ordovician)
Rock types: felsic volcanic and mafic volcanic
Elevation: 1,680 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 Tunnel Brook

Best months: April to October. Typical highs run 76°F in midsummer and 25°F in midwinter, with winter lows near 6°F.

Climate normals: NOAA 1991-2020 monthlies, BENTON 5 SW station (5 mi away), adjusted for elevation.

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 Tunnel Brook

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

Nearby rockhounding spots

Other rockhounding spots within driving distance of Tunnel Brook.

Across the state line from Tunnel Brook

Tunnel Brook is close enough to the New Hampshire border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Tunnel Brook FAQ

Where is Tunnel Brook?+

Tunnel Brook is in Grafton County, New Hampshire, at 44.09300, -71.90000. Nearest road: Tunnel Brook Road.

What rocks and minerals can you find at Tunnel Brook?+

Tunnel Brook is reported to produce Gold Placer, Gold Nugget.

Is collecting allowed at Tunnel Brook?+

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. Always confirm current rules with the managing agency before a trip.

What tools should I bring to Tunnel Brook?+

A gold pan, a classifier screen, a small shovel, and a snuffer bottle cover the basics. Motorized equipment and sluices fall under separate rules in most states, so start with hand tools.

When is the best time to visit Tunnel Brook?+

The most comfortable months at Tunnel Brook are April to October.

How do I get to Tunnel Brook?+

Open the directions link to navigate to 44.09300, -71.90000 in Google Maps. The nearest road is Tunnel Brook Road.

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