Pennsylvania Highlands Geology

The Pennsylvania Highlands are the foothills of the Appalachian Mountains. The irregular ridges and deep valleys of this unique landscape feature common themes that reflect the region’s geology, which has influenced local history and land use. Much of the Pennsylvania Highlands are comprised of the Reading Prong Geologic Formation. The Reading Prong is found primarily in Berks, Bucks, Montgomery, and Northampton Counties.

Two types of rock are common to the erosion resistant, largely forested ridges of the Pennsylvania Highlands: diabase (basalt), and granitic gneiss and quartzite (see map). The diabase areas create natural limitations for agriculture and land development, due to the size and abundance of boulders. As a result, these areas feature large contiguous woodlands such as Hopewell Big Woods and Unami Hills.

The high iron content in the gneiss and quartzite rock ridges provided the raw material for the region’s industrial legacy of iron and steel. This legacy is reflected in the names of towns, historic sites and parks found throughout all thirteen counties of the Pennsylvania Highlands region: places such as Durham Furnace, Coventry Forge, Hopewell Furnace, Johanna Furnace, Cornwall Furnace, and Pine Forge Furnace. The desire for a recreation resource to connect these historic areas and unique natural resources was the impetus for development of the Highlands Trail in Pennsylvania. The unique combination of forests, rocky hills, historic sites, industrial towns, and fertile limestone valleys makes for a compelling story told through interpretive signage and online tools, enhancing the experience of trail users.

Diabase boulders along the Unami Creek, Montgomery County

News

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AMC's Protect the View Campaign Launches

The online campaign, Protect the View, seeks to build awareness and support for the protection of trail views and experiences within the greater Philadelphia area’s Circuit Trails network.  Read More

Upper Bucks Rail Trail Opens

A ribbon cutting ceremony was held in Richland Township to celebrate the opening of a new section of the Highlands Trail in upper Bucks County. Read More

PA Outdoor Corps in the Highlands

Pennsylvania Outdoor Corps member Kayla Snyder writes about this season’s work in the Highlands at Pine Grove Furnace State Park. Read More

AMC and Partners Produce Trail Feasiblity Study

Grant funding from the Schuylkill Highlands Conservation Landscape funded a trail feasiblity study in Upper Bucks County. Read More