Onomonee Road Beach: Charlevoix Stone & Stromatolite Rockhounding in Leelanau County, Michigan

Updated August 2026

Onomonee Road Beach is a mapped rockhounding spot in Leelanau County, Michigan. Reported finds include charlevoix stone, stromatolite, stromatoporoid, fossils, chert, and more. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Leelanau County
State: Michigan
Postcode: 49674
Coordinates: 45.11297, -85.67549

Geology at Onomonee Road Beach

This spot sits on Traverse Group, mapped as limestone that formed roughly 395 to 385 million years ago. Limestone like this typically forms in ancient seas, so marine fossils such as brachiopods, corals, and crinoids tend to weather out of fresh exposures.

Mapped unit: Traverse Group
Age: 395–385 Ma (Middle Devonian)
Rock types: limestone
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 Onomonee Road Beach

Best months: April to November. Typical highs run 76°F in midsummer and 29°F in midwinter, with winter lows near 19°F.

Climate normals: NOAA 1991-2020 monthlies, NORTHPORT 2W station (2 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 Onomonee Road Beach

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 Onomonee Road Beach.

Onomonee Road Beach FAQ

Where is Onomonee Road Beach?+

Onomonee Road Beach is in Leelanau County, Michigan, at 45.11297, -85.67549.

What rocks and minerals can you find at Onomonee Road Beach?+

Onomonee Road Beach is reported to produce Charlevoix Stone, Stromatolite, Stromatoporoid, Fossils, Chert, Petoskey Stone.

Is collecting allowed at Onomonee Road Beach?+

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 Onomonee Road Beach?+

A rock hammer, a cold chisel, safety glasses, and newspaper or foam for wrapping finds cover most fossil ground. A trowel and a sieve help in soft exposures.

When is the best time to visit Onomonee Road Beach?+

The most comfortable months at Onomonee Road Beach are April to November.

How do I get to Onomonee Road Beach?+

Open the directions link to navigate to 45.11297, -85.67549 in Google Maps. Some spots are remote, so check road conditions before driving out.

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