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

Updated July 2026

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.

Area Around Caledonia State Park photos

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

1 photo

The entrance to Caledonia State Park in Franklin County, Pennsylvania

Quick details

Access: Public area
County: Franklin County
State: Pennsylvania
Nearest road: Chambersburg Water Line Trail
Postcode: 17222
Coordinates: 39.91197, -77.49838

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.

Best time to visit Area Around Caledonia State Park

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.

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 Area Around Caledonia State Park

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 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.

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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Open Area Around Caledonia State Park on the map

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