Gratiot River County Park: Freda Sandstone & Basalt Rockhounding in Keweenaw County, Michigan

Updated August 2026

Gratiot River County Park is a mapped rockhounding spot in Keweenaw County, Michigan. Reported finds include freda sandstone, basalt, rhyolite, unakite, granite, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Keweenaw County
State: Michigan
Coordinates: 47.34369, -88.45254

Best time to visit Gratiot River County 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 (12 mi away), adjusted for elevation.

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.

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 Gratiot River County 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 Gratiot River County Park.

Across the state line from Gratiot River County Park

Gratiot River County 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.

Pigeon PointCook County, Minnesota · 67 mi awayChalcocite, Chalcopyrite, Pyrite

Gratiot River County Park FAQ

Where is Gratiot River County Park?+

Gratiot River County Park is in Keweenaw County, Michigan, at 47.34369, -88.45254.

What rocks and minerals can you find at Gratiot River County Park?+

Gratiot River County Park is reported to produce Freda Sandstone, Basalt, Rhyolite, Unakite, Granite, Lake Superior Agate, Prehnite, Mesolite.

Is collecting allowed at Gratiot River County Park?+

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 Gratiot River County 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 Gratiot River County Park?+

The most comfortable months at Gratiot River County Park are April to October.

How do I get to Gratiot River County Park?+

Open the directions link to navigate to 47.34369, -88.45254 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in Michigan

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Open Gratiot River County Park on the map

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