Hillsborough River: Brain Coral & Finger Coral Rockhounding in Hillsborough County, Florida
- Minerals reported
- 3
- Elevation
- 50 ft
The Tampa Bay area is the third of Florida's classic agatized coral regions, and the Hillsborough River drainage yields silicified corals and agate along with brain and finger coral fossils. Much of the finest Tampa Bay agatized coral came from dredging, but river gravel and construction cuts still produce chalcedony-filled coral heads. Agatized coral is an invertebrate fossil and needs no state permit. Reported finds include brain coral, finger coral, agate. Below: coordinates, access notes, nearby spots, and trip-planning links.
Plan your visit
Generally open to casual rockhounding
- County
- Hillsborough County
- State
- Florida
- Nearest road
- Temple Terrace Highway
- Postcode
- 33637
- Coordinates
- 28.03209, -82.38108
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.
Access note: Public river and shoreline access outside park boundaries. Collecting is prohibited inside Hillsborough River State Park, so use public launches, rights-of-way, and exposed banks elsewhere on the drainage. Invertebrate fossils need no permit.
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.
Geology at Hillsborough River
This spot sits on Hawthorn Group, Arcadia Formation, Tampa Member, mapped as limestone that formed roughly 28 to 12 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
- Hawthorn Group, Arcadia Formation, Tampa Member
- Age
- 28–12 Ma (Late Oligocene to Middle Miocene)
- Rock types
- limestone
- Elevation
- 50 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.
Today's weather
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The app shows live weather, recent rain, and a daily rockhounding score for Hillsborough River.
Get the appSources & 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.
- Florida Geological Survey
- Florida Museum vertebrate fossil permit
- Florida State Parks rules
- Community submissions reviewed against published agency rules
Found at Hillsborough River
Each name opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.
Brain Coral
Finger Coral
AgateEncyclopedia →
Nearby rockhounding spots
Other rockhounding spots within driving distance of Hillsborough River.
- Unnamed Area (Agatized Coral #1)Hillsborough County, Florida · 12 mi awayAgatized Coral, Geode
- Unnamed Area (Agatized Coral #2)Hillsborough County, Florida · 12 mi awayAgatized Coral, Coral, Chalcedony
- Pasco CountyPasco County, Florida · 23 mi awaySilicified Coral
- Caledesi Causeway BanksPinellas County, Florida · 26 mi awayChalcedony
- Flor-a-MarPasco County, Florida · 26 mi awayAgatized Coral, Chalcedony
- DunedinPinellas County, Florida · 28 mi awayGeode
- Pinellas & Hillsborough BeachesPinellas County, Florida · 30 mi awayAgate, Carnelian, Chalcedony
- LakelandPolk County, Florida · 31 mi awayChalcedony, Silicified Coral
Hillsborough River FAQ
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