The Slate Belt


"Pennsylvania's Slate Belt is the quintessential intersection of geology, technology, and culture. It was an important part of American life and its stories are still accessible through the visual testimony of the land, the structures, and the machinery, as well as the stories of those who last labored there."


Frank Matero - Project Director

Graduate Program in Historic Preservation - University of Pennsylvania

The Diamond Slate Company of Pen Argyl. Click on the image to open it in a larger zoomable format. (To zoom in and out hold down the CTRL button on the keyboard and use the roller wheel on the mouse).Image Source: Mike Piersa

The Pennsylvania “Slate Belt,” an area of only 22 square miles, lies approximately 50 miles to the northwest of Philadelphia and just south of Blue (Kittanning) Mountain between the Delaware and Lehigh Rivers. The first quarries opened in the 1830s, but significant growth followed in the first decade of the twentieth century when Lehigh Valley accounted for approximately half the slate produced in the United States, eventually becoming the greatest slate producing region in the world.

T. Nelson Dale, Slate in the United States, 1914


The Impetus

This project was originally conceived as a University of Pennsylvania studio in Industrial Heritage at the Graduate Program in Historic Preservation. With generous funding from the J. M. Kaplan Fund, Professor Frank Matero and a group of 10 students investigated the history of the slate industry in Pennsylvania. With the vast majority of the quarries of the region (more than 350 in total) having closed by the mid 1980's, the region's slate quarrying legacy was in serious decline. The studio effort focused primarily on one quarry, American Bangor, which first opened in 1875 and still retains much of its original equipment including the incline cableways used to lift the massive pieces of slate from within the deep quarries, and a system which was unique to the slate quarries of the Pennsylvania Slate Belt. Some of the data collected during this class has been incorporated into this website.

A logo which appeared on the back of the Slate Centennial program for the centennial event held in Bangor in 1936 when the industry was still strong.

A Landscape of Extraction

The Lehigh Valley’s extractive industries of coal, iron, cement and slate created a much altered landscape with vast and deep quarries, enormous kilns, and mill buildings in a complex landscape that allows for the exploration of architectural, ecological, and socio-cultural considerations. As proven elsewhere, this industrial legacy holds the key to revitalization of the region by “regeneration through heritage,” not only in the preservation and possible re-use of these sites, but as catalysts for reviving and maintaining the social and cultural fabric of their surrounding communities and natural environment. Cultural and environmental conservation have become powerful partners in the reclamation of this complex place through ecological and social as well as architectural concerns.


The interior of a derelict hoist house at the Big Bed Slate Company, 2017.
Image Source: Joseph Elliott

In conjunction with the efforts of the students and faculty at the University of Pennsylvania, a team of students from Muhlenberg College, under Professor Joseph Elliott, Professor of Fine Arts, who documented both the few active quarries, as well as the residents of the communities that make up the Slate Belt district. The final result of that effort produced a web page called Slate Stories that showcased the photography and documentation carried out by the students.


Much of the information for this website has been collected and quoted from primary documents that were created in response to, and as a result of, this massive industry which existed for more than a century from the early 1830's until its ultimate demise during the decades after World War II. The Pennsylvania Slate quarries produced the largest output in the world but during World War I, many of the slate firms closed to release men for other essential war work, especially in the Bethlehem Steel plant nearby. Most of the quarries that closed, never reopened after the World War I as modern synthetic materials such as asphalt composites and plastics proved less expensive and easier to use, and required less skilled labor to fabricate and install. The long history of the slate industry is complex, involving a wide range of forces from the local to the global. No industry of this scale ceases to exist over night and it was not a single event that undid this once important resource. This site attempts to shed light on the elements that drove the slate belt to such significance as well as the forces that lead to its demise.




It is our intention that this site will continue to expand and be modified to reflect the growing wealth of historic information available on the subject.

The incline cableway - Once a standard of the Pennsylvania slate industry, the three headframes at American Bangor are some of only standing machinery in the entire Slate Belt region. The hoist sheds are located behind each of the head frames and the signal shed is clearly visible in the foreground.
Image Source: Joseph Elliott

Industrial Heritage

Why invest in preserving these former industrial landscapes?

First, their continued physical existence is critical to understanding how the region took shape physically, socially, economically, and culturally, more than any text or photograph can convey: real structures in real landscapes. Second, these early twentieth century sites extend the region and country’s industrial narrative from the classic eighteenth and nineteenth century notion of industrial heritage to those complexes that were responsible for America’s emergence as the world power by the latter twentieth century. Third, although the twentieth century is better documented than any other century in word and image, analog and digital, the industrial artifact and place, where they survive together, still remain the primary locus for analysis and interpretation.


"By taking a cultural landscape approach to the analysis and redevelopment of these overlapping industries, we acknowledge their original premise of natural resource extraction and exploitation in the deconstruction and construction of the land."


The Headworks at Parsons Quarry, August 1, 1924
Image Source: Pennsylvania Geological Survey

Cultural and environmental conservation become powerful partners in the reclamation of this complex place through ecological and social as well as architectural technological concerns.

In order to bring a more critical approach to the preservation of the most important and iconic of American industrial sites as recommended by the 2010 Symposium Industrial Heritage Retooled, this project proposed to address an important and understudied class of 20th century industrial heritage: the extractive industries.


"The intent is to produce a well-documented and methodologically driven website that clearly identifies the critical components of this neglected large-scale industrial landscape."


The geo-survey, mapping, and architectural documentation, all supported on a digital platform makes this information assessible in a new and inovative way. Hopefully this data will be used to advocate support for preservation at the site and community levels through exhibition, publication, and a public meetings. Web site access will help establish dissemination and influence of the findings of the project. Since the intent is to provide an accurate depiction of what the slate industry was, much of the content of this website has been extracted directly from sources which were written by those who had direct involvement with the industry. An advisory committee including former PHMC director Brenda Barrett, Robert Melnick, Professor and former Dean of Landscape, University of Oregon, Fred Quivik, Professor of History at Michigan Technological University, and Shaun Eyring, Landscape Architect. NPS will assist the project as needed. Partners in this project include: the National Park Service-Historic American Landscape Survey (HALS) and the Historic American Engineering Record (HAER) as well as the Pennsylvania Historical and Museum Commission, the Delaware and Lehigh National Heritage Corridor, and local community partners, including the Slate Belt Heritage Center in Bangor, PA.


Workers at Big Bed quarry splitting layers in the pit, 2017.
Image Source: Joseph Elliott


A Viable Legacy

Today only a handful of the old slate quarries remain active. Big Bed Slate, still in operation, is one of the oldest and best preserved of the early operations with its Victorian crane hoists, steam and electric machinery and mill shops, and extensive series of former and active quarries. This company, still economically viable, and interested in spearheading the valley’s industrial history, offers a unique opportunity together with the Slate Belt Heritage Center in Bangor, PA to document that legacy through a creative mix of preservation and economic development.

Pennsylvania’s slate belt exists within the Delaware and Lehigh National Heritage Corridor (D&LNHC), created in 1988. Despite this relationship, this conjoined landscape falls outside the Corridor’s main 165 mile trail and primary narrative dedicated to the coal, iron and steel industries and the canal and railroad networks that helped build them. This digital project seeks to work within the existing framework and partner with the D&LNHC to expand the potential of the Corridor and proposed area .