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 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

iNaturalist Projects in the PA Highlands

Combining the value of citizen science with species identification, iNaturalist gives everyday people the ability to connect with their local environment and identify the flora and fauna they observe. Read More

National Public Lands Day 2020: More Ways to Connect to Nature

This year’s NPLD will look a little different, but it’s largely virtual format will give people in or near the Pennsylvania’s Highlands region plenty of opportunities to engage in a celebration and appreciation of our public lands, while contributing to volunteer efforts from behind their computer. Read More

Great American Outdoors Act signed into Law

On August 4th, 2020 GAOA was enacted into law! This measure provides full, permanent dedicated funding for the Land and Water Conservation Fund and a $5.9B investment over 5 years to address the maintenance backlog on public lands. Read More