Historic Overview


Slate Belt of Pennsylvania Small

by Amanda Quinn

The Slate Belt of Pennsylvania lies at the base of Blue Mountain, a ridge of the Appalachians, and contains numerous beds of quality slate.  Started in the mid-nineteenth century in Bangor, PA by immigrants from Wales, the slate industry spread rapidly to nearby towns.  Slate was used for a number of purposes, including blackboards and flooring, but mainly it was used as roofing tile, because of its durability. Roofs made of slate can last hundreds of years.

Slate production grew steadily, and at its peak in the early twentieth century generated millions of dollars yearly.  Since slate requires extensive labor to quarry, it employed thousands of men and contributed to the immigration of many groups to the area. Hundreds of quarries supported entire towns across the northern Lehigh Valley.  Arguably, slate played a significant role in building up Pennsylvania’s economy. In the early 1900’s asphalt roofing tiles were invented. They were cheaper, lighter and easier to install than slate tiles. Production slowed during WWI, due to less demand for new houses and a lack of labor as men went off to war. Almost all slate quarries in Pennsylvania are now abandoned. Penn Big Bed Slate Company operates the two remaining active quarries in Slatedale and Pen Argyl, using processes have changed little since the beginning of the industry.

As was typical of Pennsylvania mining regions, the towns of the slate belt also became prime locations for the textile and garment industries. An industrious workforce and close proximity to the fashion hub in New York City provided excellent conditions for establishing fabric mills and garment factories. Even as the slate mines continued to decline after World War II, the garment factories thrived into the 1970s. After the near disappearance of garment factories in the region, there is now a resurgence of refurbished small factories in Roseto, Bangor, and Allentown.

Photographs by Bliss, Easton, PA. Courtesy of Slate Belt Heritage Center.

Historic Maps of Slate Region