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Area Around Caledonia State Park: Agate & Jasper Rockhounding in Franklin County, Pennsylvania

Public accessBest spot2 mineralsFranklin County, PennsylvaniaUpdated July 2026
Minerals reported
2
Elevation
1,110 ft
Best months
March to November

The ridges of Michaux country around Caledonia in Franklin County shed agate and jasper into local streams and float, a byproduct of the region's iron-rich Blue Ridge geology. It offers scenic, forested collecting for colorful lapidary material. This is a well-loved south-central Pennsylvania hunting ground. Reported finds include agate, jasper. Below: coordinates, access notes, nearby spots, and trip-planning links.

Plan your visit

Generally open to casual rockhounding

Nearest road
Chambersburg Water Line Trail
Postcode
17222
Get directionsView on Google Maps

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: Collecting is prohibited inside Caledonia State Park itself; hunt loose float on the surrounding state forest and public land where limited personal collecting is allowed. Verify current DCNR rules and stay off private and posted parcels.

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 Area Around Caledonia State Park

Comfortable months (45 to 90°F highs)

Best months: March to November. Typical highs run 82°F in midsummer and 37°F in midwinter, with winter lows near 22°F.

Climate normals: NOAA 1991-2020 monthlies, S MTN station (4 mi away), adjusted for elevation.

Geology at Area Around Caledonia State Park

This spot sits on Montalto Member of Harpers Formation, mapped as quartzite that formed roughly 540 to 485 million years ago. Metamorphic rock like this weathers into resistant float, and minerals that survive transport typically concentrate in nearby drainages.

Mapped unit
Montalto Member of Harpers Formation
Age
540–485 Ma (Cambrian)
Rock types
quartzite
Elevation
1,110 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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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.

Found at Area Around Caledonia State Park

Each name 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 Area Around Caledonia State Park.

Across the state line from Area Around Caledonia State Park

Area Around Caledonia State Park is close enough to the Pennsylvania border that the next-closest rockhounding spots are in a neighboring state. Worth knowing if you are already on the road.

  • Catoctin MountainFrederick County, Maryland · 18 mi awayCopper
  • MiddlesburgeCarroll County, Maryland · 26 mi awayChrysocolla
  • AshtonWashington County, Maryland · 28 mi awaySerpentine, Steatite
  • Union BridgeCarroll County, Maryland · 30 mi awayPink Marble, Green Marble
  • MiddletownFrederick County, Maryland · 33 mi awayStibnite
  • New WindsorCarroll County, Maryland · 33 mi awayAzurite, Bornite, Calamine

Area Around Caledonia State Park FAQ

Where is Area Around Caledonia State Park?+
Area Around Caledonia State Park is in Franklin County, Pennsylvania, at 39.91197, -77.49838. Nearest road: Chambersburg Water Line Trail.
What rocks and minerals can you find at Area Around Caledonia State Park?+
Area Around Caledonia State Park is reported to produce Agate, Jasper.
Is collecting allowed at Area Around Caledonia State Park?+
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 Area Around Caledonia State Park?+
Most agate and jasper is surface float: bring a spray bottle, a pick or small shovel, and a sturdy bag. Wet stones show their banding and translucence.
When is the best time to visit Area Around Caledonia State Park?+
The most comfortable months at Area Around Caledonia State Park are March to November.
How do I get to Area Around Caledonia State Park?+
Open the directions link to navigate to 39.91197, -77.49838 in Google Maps. The nearest road is Chambersburg Water Line Trail.

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