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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Recorded Webinar: "In Defense of Public Lands: Some Lessons on its Biological, Economic, and Social Value"

Watch the webinar from early June 2020 hosted by the PA Highlands Coalition, which featured Author and Professor of Political Science Steven Davis. Read More

AMC Produces Highlands Trail StoryMap

Using ESRI’s ArcGIS StoryMap platform, AMC staff prepared a custom interactive map that tells the story of the 300-mile long Highlands Trail in Pennsylvania. Read More

Recorded Webinar: "Protection of the Kittatinny Ridge: A Global Important Bird Area"

Watch the webinar from early April 2020 to learn more about the Kittatinny Ridge Conservation Landscape, northern neighbor to the PA Highlands region. Read More

Highlight the Highlands: Nolde Forest Expanded

Located in the middle of the Pennsylvania Highlands region, Nolde Forest Environmental Education Center boasts woodlands that are over 100 years old and it will now include 60 additional acres supported with funding from PA Bureau of State Parks and the federal Highlands Conservation Act. Read More