Antrim Creek Natural Area: Petoskey Stone & Charlevoix Stone Rockhounding in Antrim County, Michigan

Plan your visit

Generally open to casual rockhounding

County

Antrim County

State

Michigan

Postcode

49729

Coordinates

45.17907, -85.37866

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 Antrim Creek Natural Area

Comfortable months (45 to 90°F highs)

Best months: April to November. Typical highs run 76°F in midsummer and 29°F in midwinter, with winter lows near 17°F.

Climate normals: NOAA 1991-2020 monthlies, CHARLEVOIX station (11 mi away).

Geology at Antrim Creek Natural Area

This spot sits on Antrim Shale, mapped as black shale that formed roughly 385 to 360 million years ago. Sedimentary layers like these are where fossils are typically preserved, and fresh exposures after rain or in active cuts tend to produce best.

Mapped unit

Antrim Shale

Age

385–360 Ma (Late Devonian)

Rock types

black shale

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.

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