Red Shirt: Agate & Chalcedony Rockhounding in Oglala Lakota County, South Dakota

Plan your visit

Permission required before collecting

County

Oglala Lakota County

State

South Dakota

Nearest road

Tatanka Numpa Road

Coordinates

43.67413, -102.89909

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

Land & collecting status

Permission required before collecting

Requires landowner or agency permission before any collecting. Do not enter without explicit authorization.

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 Red Shirt

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 90°F in midsummer and 39°F in midwinter, with winter lows near 12°F.

Climate normals: NOAA 1991-2020 monthlies, ORAL station (26 mi away), adjusted for elevation.

Geology at Red Shirt

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

2,660 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