Link to PA Geological Survey
Pennsylvania’s Trail of Geology
- Trough State Park (PG 1) Huntingdon County, Ridge and Valley province—Ice Mine and Balanced Rock erosional remnant.
- Hickory Run State Park (PG 2) Carbon County, on the Pocono Plateau—Hickory Run Boulder Field, created by periglacial activity during the Ice Age.
- Archbald State Park (PG 3) Northeast of Scranton in Lackawanna County—the world’s largest pothole, discovered in 1884.
- Moraine and McConnells Mill State Parks (PG 4; also includes the former PG 9) (On-line version) Butler and Lawrence Counties—glacial lakes and drainage changes.
- Moraine and McConnells Mill State Parks (PG 4; also includes the former PG 9) (PDF version) Butler and Lawrence Counties—glacial lakes and drainage changes.
- Leonard Harrison and Colton Point State Parks (PG 5) Tioga County, north-central Pennsylvania—the Grand Canyon of Pennsylvania.
- French Creek State Park (PG 6) Berks and Chester Counties—Piedmont rocks and the Hopewell Furnace.
- Ohiopyle State Park (PG 7) Along the Youghiogheny River in Fayette County—waterfalls, Devonian-age rocks, and the Laurel Hill anticline.
- Valley Forge National Historical Park (PG 8) Montgomery and Chester Counties—Port Kennedy quarry and Valley Creek Gorge.
- Gifford Pinchot State Park (PG 10) York County—diabase (molten, liquid rock).
- Ravensburg State Park (PG 11) Clinton County—Rocky Gorge, Castle Rocks, and Big Rock Spring.
- Worlds End State Park (PG 12) Sullivan County—Loyalsock Gorge, fossils, and the Rock Garden.
- Ricketts Glen State Park (PG 13) Luzerne, Sullivan, and Columbia Counties—the Red Rock, Midway Crevasse, and The Glens, which has 25 distinct waterfalls.
- Nockamixon State Park (PG 14) Bucks County—Sentinel Rock, Tohickon quarry, joints, ledges, and boulders.
- Caledonia and Pine Grove Furnace State Parks (PG 15) Cumberland, Adams, and Franklin Counties—the iron ore industry, faults, and the Tomstown Dolomite.
- Swatara State Park (PG 16) Lebanon and Schuylkill Counties—includes a site where you may collect fossils, including (if you are lucky) Phacops rana, the State Fossil.
- Samuel S. Lewis State Park (PG 17) York County—Chickies Rock, Mt. Pisgah, and the Lower Susquehanna Valley.
- Promised Land State Park (PG 18) Pike County, on the Pocono Plateau—ancient rivers and ages of ice.
- Raymond B. Winter State Park (PG 19) Union County—scenery, rocks, and springs in eastern Brush Valley.
- White Clay Creek Preserve (PG 20) Chester County, Pennsylvania, and New Castle County, Delaware—the Wissahickon Formation and pegmatites.
- Presque Isle State Park (PG 21) Erie County—evidence of past and present geologic processes.
- Oil Creek State Park (PG 22) The geologic heritage of Pennsylvania’s oil region, and the geologic history of Oil Creek.
- Lehigh Gorge State Park Open-File Report 98–03, Rocks and ruins of the “Upper Grand”—An illustrated trail guide to the geology and historical archeology of Lehigh Gorge State Park.
- Point State Park Older brochure, prepared for the Pittsburgh Geological Society by the University of Pittsburgh—features the structure of “The Point.”
Garrett-to-Rockwood section of the Allegheny Highlands Trail —Prepared by the Pennsylvania Geological Survey in cooperation with the Somerset County Rails-to-Trails Association and the Somerset County Parks and Recreation Board—diverse geologic topics (formation of rock units, structure and age of rocks, types of fossils, and more) along a 7-mile section of the Allegheny Highlands Trail in Somerset County.