McClain State Park: Adularia & Chalcedony Rockhounding in Houghton County, Michigan

Updated August 2026

McClain State Park is a mapped rockhounding spot in Houghton County, Michigan. Reported finds include adularia, chalcedony, chert, jasper, keweenaw agate, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Permission required
County: Houghton County
State: Michigan
Nearest road: Bear Lake Road
Postcode: 49930
Coordinates: 47.23683, -88.61473

Geology at McClain State Park

This spot sits on Oronto Group; Freda Sandstone, mapped as shale, siltstone, and arkose that formed roughly 1600 to 1000 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.

Mapped unit: Oronto Group; Freda Sandstone
Age: 1600–1000 Ma (Mesoproterozoic)
Rock types: shale, siltstone, and arkose
Elevation: 590 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 McClain State Park

Best months: April to October. Typical highs run 77°F in midsummer and 24°F in midwinter, with winter lows near 12°F.

Climate normals: NOAA 1991-2020 monthlies, HANCOCK HOUGHTON CO AP station (8 mi away), adjusted for elevation.

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.

State guidance last verified: April 1, 2026

Michigan DNR — Rockhounding rules
Michigan Geological Survey
Isle Royale National Park — Rules
Community submissions reviewed against published agency rules

Found at McClain State Park

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 McClain State Park.

Across the state line from McClain State Park

McClain State Park is close enough to the Michigan border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

McClain State Park FAQ

Where is McClain State Park?+

McClain State Park is in Houghton County, Michigan, at 47.23683, -88.61473. Nearest road: Bear Lake Road.

What rocks and minerals can you find at McClain State Park?+

McClain State Park is reported to produce Adularia, Chalcedony, Chert, Jasper, Keweenaw Agate, Thomsonite, Prehnite, Quartz, Rhyolite, Granite, Lake Superior Agate.

Is collecting allowed at McClain State Park?+

Permission required before collecting. Requires landowner or agency permission before any collecting. Do not enter without explicit authorization. Always confirm current rules with the managing agency before a trip.

What tools should I bring to McClain State Park?+

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 McClain State Park?+

The most comfortable months at McClain State Park are April to October.

How do I get to McClain State Park?+

Open the directions link to navigate to 47.23683, -88.61473 in Google Maps. The nearest road is Bear Lake Road.

More rockhounding in Michigan

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Open McClain State Park on the map

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