Esrey Park: Granite & Prehnite Rockhounding in Keweenaw County, Michigan
- Minerals reported
- 4
- Elevation
- 610 ft
- Best months
- April to October
Esrey Park is a mapped rockhounding spot in Keweenaw County, Michigan. Reported finds include granite, prehnite, copper, agate nodule. Below: coordinates, access notes, nearby spots, and trip-planning links.
Plan your visit
Generally open to casual rockhounding
- County
- Keweenaw County
- State
- Michigan
- Nearest road
- M 26
- Coordinates
- 47.46864, -88.05672
Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.
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.
Best time to visit Esrey Park
Comfortable months (45 to 90°F highs)
Best months: April to October. Typical highs run 72°F in midsummer and 26°F in midwinter, with winter lows near 15°F.
Climate normals: NOAA 1991-2020 monthlies, COPPER HARBOR station (8 mi away).
Geology at Esrey Park
This spot sits on Copper Harbor Conglomerate; Volcanic member, mapped as basaltic andesite that formed roughly 1600 to 1000 million years ago. Volcanic ground like this is where agate, jasper, and other chalcedony typically form, filling old gas pockets and fracture seams in the flow rock.
- Mapped unit
- Copper Harbor Conglomerate; Volcanic member
- Age
- 1600–1000 Ma (Mesoproterozoic)
- Rock types
- basaltic andesite
- 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.
Today's weather
Is today a good day to go?
The app shows live weather, recent rain, and a daily rockhounding score for Esrey Park.
Get the appSources & 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:
- Michigan DNR, Rockhounding rules
- Michigan Geological Survey
- Isle Royale National Park, Rules
- Community submissions reviewed against published agency rules
Found at Esrey Park
Each name 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 Esrey Park.
- Central MineKeweenaw County, Michigan · 8 mi awayCopper, Chlorastrolite
- Cliff NorthKeweenaw County, Michigan · 14 mi awayCopper, Calcite, Chlorite
- Cliff MineKeweenaw County, Michigan · 14 mi awayCopper, Calcite, Chlorite
- Keweenaw Rocket RangeKeweenaw County, Michigan · 16 mi awayGranite, Prehnite, Copper
- High Rock BayKeweenaw County, Michigan · 16 mi awayPrehnite, Calcite, Copper
- Keweenaw PointKeweenaw County, Michigan · 17 mi awayKeweenaw Agate, Thomsonite, Datolite
- Iroquois MineKeweenaw County, Michigan · 17 mi awayNative Copper
- Seneca No. 1 ShaftKeweenaw County, Michigan · 18 mi awayCopper, Datolite, Prehnite
Across the state line from Esrey Park
Esrey 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.
Esrey Park FAQ
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More rockhounding in Michigan
See all 119 Michigan spots →
Open Esrey Park on the map
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