• Photo of Lemon House, Level #6, and Engine House on a beautiful summer day.

    Allegheny Portage Railroad

    National Historic Site Pennsylvania

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  • Road Closure

    Please be aware that part of the public area loop has been closed until further notice as the park starts preparatory efforts for this summer's paving project on the Picnic Area Road.

Natural Features & Ecosystems


The mountainous terrain of the Allegheny Mountain section of the Appalachian Plateau posed a problem to the Pennsylvania Mainline Canal, leading to the creation and use of incline planes that came to be known as the Allegheny Portage Railroad. The terrain-influenced form of transit, once novel and innovative for its time, is the backbone of the park’s history.

The Main Unit of Allegheny Portage Railroad NHS lies on a dividing ridge of the Allegheny Mountains that separates two major drainage basins: the Chesapeake Bay Watershed and the Ohio River basin. The headwaters to Blair Gap Run, which eventually flow to the Susquehanna River and the Chesapeake Bay, are found within the park. At the Staple Bend Tunnel Unit, seeps and intermittent streams are found along the historic railroad trace, which is now a hiking and biking trail. These flow into the Little Conemaugh River, which eventually joins the Ohio River.

Did You Know?

drawing of the South Fork Dam

The dam at South Fork, PA, that broke causing the Johnstown Flood of 1889 was originally built for the Mainline Canal System. The Allegheny Portage Railroad was an important part of the Mainline, so the stories are interconnected.