Caesar Creek Lake Spillway: Fossil Hunting in Warren County, Ohio
Updated July 2026
The emergency spillway below Caesar Creek dam cut through Upper Ordovician bedrock and exposed one of the richest fossil beds in the eastern United States, packed with brachiopods, bryozoans, crinoids, horn corals, and the trilobite Isotelus, the animal Ohio adopted as its state invertebrate fossil. The U.S. Army Corps of Engineers opens the spillway to the public and lets visitors keep loose surface fossils, a rare exception on Corps land. Winter freeze and thaw constantly break up the shale, so the exposure re-seeds itself with fresh material every spring. Reported finds include fossils, trilobites, brachiopods, crinoids, bryozoans. Below: coordinates, access notes, nearby spots, and trip-planning links.
Caesar Creek Lake Spillway photos
Public image records connected to this spot or its reported material.
Map showing Caesar Creek Lake Spillway in Warren County, Ohio
Quick details
- Access
- Public area
- County
- Warren County
- State
- Ohio
- Nearest road
- North Clarksville Road
- Postcode
- 45068
- Coordinates
- 39.48778, -84.06403
Geology at Caesar Creek Lake Spillway
This spot sits on Drakes, Whitewater and Liberty Formations, Undivided, mapped as shale and limestone that formed roughly 455 to 445 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
- Drakes, Whitewater and Liberty Formations, Undivided
- Age
- 455–445 Ma (Late Ordovician)
- Rock types
- shale and limestone
- Elevation
- 910 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.
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 Caesar Creek Lake Spillway
Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.
- FossilsEncyclopedia →
- Trilobites
- Brachiopods
- Crinoids
- Bryozoans
Nearby rockhounding spots
Other rockhounding spots within driving distance of Caesar Creek Lake Spillway.
- Oakes Quarry ParkTop pick in OhioGreene County, Ohio · 21 mi awayFossils, Crinoids, Brachiopods
- Trammel Fossil ParkTop pick in OhioHamilton County, Ohio · 23 mi awayFossils, Trilobites, Brachiopods
- MilfordHamilton County, Ohio · 24 mi awayDiamond
- Hueston Woods State ParkTop pick in OhioPreble County, Ohio · 37 mi awayFossils, Trilobites, Brachiopods
- Sinking SpringHighland County, Ohio · 46 mi awayHematite
- ChillicotheRoss County, Ohio · 52 mi awayPyrite
- ColumbusFranklin County, Ohio · 63 mi awayPyrite
- Delaware CountyDelaware County, Ohio · 74 mi awayPyrite
Across the state line from Caesar Creek Lake Spillway
Caesar Creek Lake Spillway 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.
Caesar Creek Lake Spillway FAQ
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More rockhounding in Ohio
See all 38 Ohio spots →Open Caesar Creek Lake Spillway on the map
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