Cobb & Mifflin: Azurite & Barite Rockhounding in Iowa County, Wisconsin

Updated June 2026

Cobb & Mifflin is a mapped rockhounding spot in Iowa County, Wisconsin. Reported finds include azurite, barite, chalcopyrite, cuprite, smithsonite, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Iowa County
State: Wisconsin
Nearest road: Bollant Road
Postcode: 53580
Coordinates: 42.88392, -90.38770

Geology at Cobb & Mifflin

This spot sits on Galena Formation, mapped as dolomite that formed roughly 470 to 460 million years ago. Carbonate rock like this dissolves and weathers readily, so fresh road cuts, quarries, and creek exposures are typically the most productive ground.

Mapped unit: Galena Formation
Age: 470–460 Ma (Middle Ordovician)
Rock types: dolomite
Elevation: 1,030 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 Cobb & Mifflin

Best months: April to October. Typical highs run 82°F in midsummer and 26°F in midwinter, with winter lows near 10°F.

Climate normals: NOAA 1991-2020 monthlies, PLATTEVILLE station (10 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 Cobb & Mifflin

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 Cobb & Mifflin.

Across the state line from Cobb & Mifflin

Cobb & Mifflin 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.

Cobb & Mifflin FAQ

Where is Cobb & Mifflin?+

Cobb & Mifflin is in Iowa County, Wisconsin, at 42.88392, -90.38770. Nearest road: Bollant Road.

What rocks and minerals can you find at Cobb & Mifflin?+

Cobb & Mifflin is reported to produce Azurite, Barite, Chalcopyrite, Cuprite, Smithsonite, Sphalerite.

Is collecting allowed at Cobb & Mifflin?+

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 Cobb & Mifflin?+

A rock hammer, gloves, and safety glasses are enough for oxidized copper ground. Look for green and blue staining on weathered rock and in old dump piles.

When is the best time to visit Cobb & Mifflin?+

The most comfortable months at Cobb & Mifflin are April to October.

How do I get to Cobb & Mifflin?+

Open the directions link to navigate to 42.88392, -90.38770 in Google Maps. The nearest road is Bollant Road.

More rockhounding in Wisconsin

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Open Cobb & Mifflin on the map

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