Grant River beds: Pearls Rockhounding in Grant County, Wisconsin

Updated July 2026

Grant River beds is a mapped rockhounding spot in Grant County, Wisconsin. Reported finds include pearls. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Check locally
County: Grant County
State: Wisconsin
Nearest road: Great River Road
Postcode: 53820
Coordinates: 42.66968, -90.74863

Geology at Grant River beds

This spot sits on Ancell Group, mapped as sandstone that formed roughly 485 to 445 million years ago. Sedimentary rock like this erodes unevenly, so the most productive collecting is typically along fresh cuts, badland slopes, and active drainages.

Mapped unit: Ancell Group
Age: 485–445 Ma (Ordovician)
Rock types: sandstone
Elevation: 610 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 Grant River beds

Best months: March to November. Typical highs run 85°F in midsummer and 28°F in midwinter, with winter lows near 10°F.

Climate normals: NOAA 1991-2020 monthlies, DUBUQUE L&D 11 station (10 mi away).

Land & collecting status

Confirm rules before collecting

Land status here is not confirmed. Verify with the managing agency before collecting — federal, state, and tribal rules differ.

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 Grant River beds

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

Pearls

Nearby rockhounding spots

Other rockhounding spots within driving distance of Grant River beds.

Across the state line from Grant River beds

Grant River beds is close enough to the Wisconsin border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

Grant River beds FAQ

Where is Grant River beds?+

Grant River beds is in Grant County, Wisconsin, at 42.66968, -90.74863. Nearest road: Great River Road.

What rocks and minerals can you find at Grant River beds?+

Grant River beds is reported to produce Pearls.

Is collecting allowed at Grant River beds?+

Confirm rules before collecting. Land status here is not confirmed. Verify with the managing agency before collecting — federal, state, and tribal rules differ. Always confirm current rules with the managing agency before a trip.

What tools should I bring to Grant River beds?+

A rock hammer, sturdy gloves, safety glasses, and a collecting bag cover the basics here. Add a spray bottle: wet rock shows color and pattern that dry rock hides.

When is the best time to visit Grant River beds?+

The most comfortable months at Grant River beds are March to November.

How do I get to Grant River beds?+

Open the directions link to navigate to 42.66968, -90.74863 in Google Maps. The nearest road is Great River Road.

More rockhounding in Wisconsin

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Open Grant River beds on the map

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