Prairie du Chien: Agate Rockhounding in Crawford County, Wisconsin

Quick details

Access

Permission required

County

Crawford County

State

Wisconsin

Coordinates

43.11533, -91.15793

Geology at Prairie du Chien

This spot sits on ground mapped as sandstone that formed roughly 540 to 485 million years ago. Tough silica like agate, jasper, and chert typically weathers out of beds like these and collects as float in drainages and on deflation surfaces.

Age

540–485 Ma (Cambrian)

Rock types

sandstone

Elevation

620 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 Prairie du Chien

Best months: March to November. Typical highs run 83°F in midsummer and 27°F in midwinter, with winter lows near 10°F.

Climate normals: NOAA 1991-2020 monthlies, PRAIRIE DU CHIEN station (5 mi away).

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.

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 Prairie du Chien

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

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