Camp Crook: Moss Agate & Chalcedony Rockhounding in Harding County, South Dakota

Plan your visit

Generally open to casual rockhounding

County

Harding County

State

South Dakota

Nearest road

SD Highway 20

Coordinates

45.55254, -103.96500

Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.

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.

Access note: Camp Crook sits along the Little Missouri River in Harding County, with scattered BLM tracts and public river-gravel bars in the area. On BLM land, rockhounds may collect rocks, minerals, and gemstones for personal use without a permit, subject to the standard 25-pound-per-day limit and hand-tools-only rule. Surrounding ranch land is heavily private and checkerboarded, so collectors should confirm parcels are BLM or a navigable riverbed before collecting and seek landowner permission elsewhere.

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.

Best time to visit Camp Crook

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 88°F in midsummer and 34°F in midwinter, with winter lows near 11°F.

Climate normals: NOAA 1991-2020 monthlies, CAMP CROOK station (1 mi away).

Geology at Camp Crook

This spot sits on Alluvium, mapped as coarse alluvium and fine alluvium that formed within roughly the last 3 million years. Gravels like these concentrate whatever survives the river: agate, jasper, and other tough silica typically show up as rounded, waxy stones.

Mapped unit

Alluvium

Age

3 Ma to present (Quaternary)

Rock types

coarse alluvium and fine alluvium

Elevation

3,110 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.

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.

• BLM Montana-Dakotas rockhounding rules
• Buffalo Gap National Grassland
• South Dakota Geological Survey
• Community submissions reviewed against published agency rules