High Rock Bay: Prehnite & Calcite Rockhounding in Keweenaw County, Michigan

Updated August 2026

High Rock Bay is a mapped rockhounding spot in Keweenaw County, Michigan. Reported finds include prehnite, calcite, copper, epidote, lake superior agate, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Keweenaw County
State: Michigan
Coordinates: 47.42327, -87.71519

Best time to visit High Rock Bay

Best months: May to October. Typical highs run 73°F in midsummer and 23°F in midwinter, with winter lows near 11°F.

Climate normals: NOAA 1991-2020 monthlies, COPPER HARBOR FT WILKINS station (8 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.

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 High Rock Bay

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 High Rock Bay.

High Rock Bay FAQ

Where is High Rock Bay?+

High Rock Bay is in Keweenaw County, Michigan, at 47.42327, -87.71519.

What rocks and minerals can you find at High Rock Bay?+

High Rock Bay is reported to produce Prehnite, Calcite, Copper, Epidote, Lake Superior Agate, Datolite, Isle Royale Greenstone.

Is collecting allowed at High Rock Bay?+

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 High Rock Bay?+

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 High Rock Bay?+

The most comfortable months at High Rock Bay are May to October.

How do I get to High Rock Bay?+

Open the directions link to navigate to 47.42327, -87.71519 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in Michigan

See all 107 Michigan spots →

Open High Rock Bay on the map

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