Cassville: Agate & Quartz Rockhounding in Grant County, Wisconsin

Updated June 2026

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

Quick details

Access: Public area
County: Grant County
State: Wisconsin
Nearest road: Brewery Hollow Road
Postcode: 53806
Coordinates: 42.72921, -90.99236

Geology at Cassville

This spot sits on Sinnipee Group, mapped as dolostone that formed roughly 485 to 445 million years ago. Chert and agate nodules typically form inside carbonate rock like this and weather out as tough, waxy lumps in soils and creek beds.

Mapped unit: Sinnipee Group
Age: 485–445 Ma (Ordovician)
Rock types: dolostone
Elevation: 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.

Best time to visit Cassville

Best months: March to November. Typical highs run 84°F in midsummer and 28°F in midwinter, with winter lows near 10°F.

Climate normals: NOAA 1991-2020 monthlies, GUTTENBERG L&D 10 station (7 mi away).

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 Cassville

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

Nearby rockhounding spots

Other rockhounding spots within driving distance of Cassville.

Across the state line from Cassville

Cassville 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.

Cassville FAQ

Where is Cassville?+

Cassville is in Grant County, Wisconsin, at 42.72921, -90.99236. Nearest road: Brewery Hollow Road.

What rocks and minerals can you find at Cassville?+

Cassville is reported to produce Agate, Quartz.

Is collecting allowed at Cassville?+

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 Cassville?+

Most agate and jasper is surface float: bring a spray bottle, a pick or small shovel, and a sturdy bag. Wet stones show their banding and translucence.

When is the best time to visit Cassville?+

The most comfortable months at Cassville are March to November.

How do I get to Cassville?+

Open the directions link to navigate to 42.72921, -90.99236 in Google Maps. The nearest road is Brewery Hollow Road.

More rockhounding in Wisconsin

See all 77 Wisconsin spots →

Open Cassville on the map

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