Ketchum: Tetrahedrite & Arsenopyrite Rockhounding in Blaine County, Idaho

Updated June 2026

Ketchum is a mapped rockhounding spot in Blaine County, Idaho. Reported finds include tetrahedrite, arsenopyrite, galena, siderite, sphalerite. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Blaine County
State: Idaho
Nearest road: National Forest Development Road 267
Postcode: 83353
Coordinates: 43.69078, -114.29386

Geology at Ketchum

This spot sits on Milligen Formation, mapped as argillite, limestone, diamictite, sandstone, black carbonaceous argillite, and carbonaceous sandstone that formed roughly 420 to 360 million years ago. Carbonate rock like this is the classic host for lead, zinc, and fluorite mineralization, which typically follows old cavities and replacement zones.

Mapped unit: Milligen Formation
Age: 420–360 Ma (Early Devonian to Late Devonian)
Rock types: argillite, limestone, diamictite, sandstone, black carbonaceous argillite, and carbonaceous sandstone
Elevation: 6,790 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 Ketchum

Best months: April to October. Typical highs run 77°F in midsummer and 28°F in midwinter, with winter lows near 5°F.

Climate normals: NOAA 1991-2020 monthlies, KETCHUM RS station (3 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.

State guidance last verified: April 1, 2026

Idaho Panhandle National Forests — Emerald Creek
Idaho Geological Survey
Spencer Opal Mines (fee-dig operator)
Community submissions reviewed against published agency rules

Found at Ketchum

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 Ketchum.

Ketchum FAQ

Where is Ketchum?+

Ketchum is in Blaine County, Idaho, at 43.69078, -114.29386. Nearest road: National Forest Development Road 267.

What rocks and minerals can you find at Ketchum?+

Ketchum is reported to produce Tetrahedrite, Arsenopyrite, Galena, Siderite, Sphalerite.

Is collecting allowed at Ketchum?+

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 Ketchum?+

A rock hammer, gloves, and safety glasses cover old mining-district ground. Stay out of shafts and adits; the best specimens typically come from dump piles.

When is the best time to visit Ketchum?+

The most comfortable months at Ketchum are April to October.

How do I get to Ketchum?+

Open the directions link to navigate to 43.69078, -114.29386 in Google Maps. The nearest road is National Forest Development Road 267.

More rockhounding in Idaho

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Open Ketchum on the map

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