Pennington County: Amethyst Rockhounding in Pennington County, South Dakota

Updated June 2026

Pennington County is a mapped rockhounding spot in Pennington County, South Dakota. Reported finds include amethyst. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Pennington County
State: South Dakota
Nearest road: Highway 1416
Postcode: 57761
Coordinates: 44.10790, -103.02447

Geology at Pennington County

This spot sits on ground mapped as Alluvial deposits that formed within roughly the last 3 million years. Loose deposits like these are float-collecting ground: erosion keeps moving durable rocks and minerals into gravel bars, cutbanks, and washes.

Mapped unit: Alluvial deposits
Age: 3 Ma to present (Pleistocene to Holocene)
Elevation: 2,990 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 Pennington County

Best months: March to November. Typical highs run 87°F in midsummer and 37°F in midwinter, with winter lows near 13°F.

Climate normals: NOAA 1991-2020 monthlies, RAPID CITY RGNL AP 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 Pennington County

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

Amethyst Encyclopedia →

Nearby rockhounding spots

Other rockhounding spots within driving distance of Pennington County.

Across the state line from Pennington County

Pennington County is close enough to the South Dakota border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Pennington County FAQ

Where is Pennington County?+

Pennington County is in Pennington County, South Dakota, at 44.10790, -103.02447. Nearest road: Highway 1416.

What rocks and minerals can you find at Pennington County?+

Pennington County is reported to produce Amethyst.

Is collecting allowed at Pennington County?+

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 Pennington County?+

A rock hammer, a small pry bar, gloves, and safety glasses cover most crystal ground. A screen helps in loose pocket soil, and newspaper protects points on the way out.

When is the best time to visit Pennington County?+

The most comfortable months at Pennington County are March to November.

How do I get to Pennington County?+

Open the directions link to navigate to 44.10790, -103.02447 in Google Maps. The nearest road is Highway 1416.

More rockhounding in South Dakota

See all 43 South Dakota spots →

Open Pennington County on the map

Use the RockHoundR app for live land overlays, weather, geology, directions, and saved finds.