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Coshocton County: Dark Gray Flint & Black Flint Rockhounding in Coshocton County, Ohio

Updated July 2026

Coshocton County is the home of Upper Mercer flint, the glossy blue-black, white-flecked chert that flint knappers prize above almost any other Ohio material and still gather at the annual Coshocton Flint Festival and Knap-In. The Pennsylvanian Upper Mercer horizon chertifies to a hard, fine-grained black flint that Paleo-Indian and later peoples worked and traded throughout the upper Ohio Valley. Weathered cobbles and nodules turn up in the county's stream gravels and plowed fields. Reported finds include dark gray flint, black flint. Below: coordinates, access notes, nearby spots, and trip-planning links.

Coshocton County photos

Public image records connected to this spot or its reported material.

1 photo

The Walhonding River at Warsaw, Coshocton County, Ohio, whose gravel bars carry Upper Mercer flint

Quick details

Access: Public area
County: Coshocton County
State: Ohio
Nearest road: County Road 55
Postcode: 43812
Coordinates: 40.27841, -81.90901

Geology at Coshocton County

This spot sits on Allegheny and Pottsville Groups, Undivided, mapped as shale and siltstone that formed roughly 325 to 300 million years ago. Sedimentary rock like this erodes unevenly, so the most productive collecting is typically along fresh cuts, badland slopes, and active drainages.

Mapped unit: Allegheny and Pottsville Groups, Undivided
Age: 325–300 Ma (Pennsylvanian)
Rock types: shale and siltstone
Elevation: 1,060 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 Coshocton County

Best months: March to November. Typical highs run 82°F in midsummer and 36°F in midwinter, with winter lows near 19°F.

Climate normals: NOAA 1991-2020 monthlies, COSHOCTON WPC PLT station (3 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.

Sources: RockHoundR public spot dataset, app land overlays, and local agency review before each trip.

Found at Coshocton County

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 Coshocton County.

Across the state line from Coshocton County

Coshocton County is close enough to the Ohio border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

New MartinsvilleWetzel County, West Virginia · 70 mi awayMuscovite

Coshocton County FAQ

Where is Coshocton County?+

Coshocton County is in Coshocton County, Ohio, at 40.27841, -81.90901. Nearest road: County Road 55.

What rocks and minerals can you find at Coshocton County?+

Coshocton County is reported to produce Dark Gray Flint, Black Flint.

Is collecting allowed at Coshocton County?+

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 Coshocton County?+

A rock hammer, sturdy gloves, safety glasses, and a collecting bag cover the basics here. Add a spray bottle: wet rock shows color and pattern that dry rock hides.

When is the best time to visit Coshocton County?+

The most comfortable months at Coshocton County are March to November.

How do I get to Coshocton County?+

Open the directions link to navigate to 40.27841, -81.90901 in Google Maps. The nearest road is County Road 55.

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