Cornwall Furnace
Cornwall, Lebanon County, Pennsylvania
Marker Inscription
Built by Peter Grubb. Operated from 1742 to 1883. Administered by the Pennsylvania Historical and Museum Commission.
Erected by Pennsylvania Historical and Museum Commission
The Story
Built by ironmaster Peter Grubb in 1742, this charcoal furnace drew on the abundant iron ore of the Cornwall hills and stayed in blast until 1883—an extraordinary run of nearly a century and a half. It smelted iron through the colonial era, the Revolution, and deep into the industrial age before finally falling cold. Today the Pennsylvania Historical and Museum Commission cares for the site as a monument to the state's ironmaking heritage.
Why it matters
Its remarkable longevity makes Cornwall a living record of how early American iron production evolved from a colonial craft into a modern industry.
The story behind this marker
AI contextThe era
When this furnace first went into blast in 1742, iron was one of the most valuable things a colony could produce for itself. The raw ingredients — ore, timber for charcoal, and limestone — were abundant in the Pennsylvania countryside, but turning them into usable metal required skill, capital, and a well-chosen site. This spot in the Cornwall hills had what an ironmaster needed.
Early furnaces were built where the resources were, which usually meant deep in rural country rather than in a town. Around the stack grew a whole working community: laborers, colliers who charred the wood, teamsters, and the roads and outbuildings that kept the operation fed. The furnace was the heart of a small, self-contained industrial world.
What sets this one apart is how long that heart kept beating. Blown in during the colonial era, it stayed in operation through the Revolution, the founding of the republic, and deep into the industrial nineteenth century — a span of roughly a century and a half.
People & events
The furnace was the work of Peter Grubb, the ironmaster who established it and put the local ore to use. Founding an ironworks in the 1740s was a serious gamble; furnaces were expensive to build, slow to repay, and unforgiving of a bad location. Grubb's venture succeeded where many did not, and it outlasted nearly all of its early rivals.
The simple span on the marker — 1742 to 1883 — is itself a kind of biography. A furnace that stays in blast that long is not a single story but many: generations of workers, changing owners, shifting technology, and constant repair and rebuilding. Each blast season was its own campaign, and to string so many of them together across 141 years is genuinely rare.
When the fires finally went cold, the site did not disappear. It came under the care of the Pennsylvania Historical and Museum Commission, the state body charged with preserving Pennsylvania's past, which keeps it as a monument to the industry that once ran here.
Its place in the American story
Iron was foundational to early America in the most literal sense — it made the tools, hardware, and implements a growing country ran on, and producing it at home reduced dependence on imported British metal. Furnaces like this one were small but real steps toward American economic independence.
The site's long working life also captures something larger: the arc from a colonial craft to a modern industry. When it opened, ironmaking was a slow, charcoal-fueled art tied to the land and the seasons. By the time it closed, the wider industry had been transformed by new fuels, new methods, and the rise of steel. A place that lived through that whole transition is a rare and valuable witness to it.
That longevity is why the furnace is preserved rather than forgotten. It stands not for one dramatic moment but for endurance — the quiet persistence of an industry that helped build the nation over generations.
If you visit
This is a place to appreciate industry and continuity rather than a single event. Focus on the furnace and its surroundings, and let the sheer span of its working life sink in — you're standing at a site that made iron across parts of three centuries.
As you look, try to imagine the same ground busy and loud: fires burning, wagons coming and going, the constant labor of keeping a furnace in blast. The stillness now is the aftermath of an operation that ran for an extraordinarily long time before it stopped.
Tucked into the countryside of Lebanon County, it makes a rewarding, unhurried stop for anyone curious about how early Americans made the metal their world depended on. Come with time to linger and read the site slowly; its story is measured in generations, not minutes.
Written by AI to add context, grounded in the marker’s inscription and the historical record. The inscription above is the original, unaltered text.
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Related people
- · Peter Grubb
Themes & tags
Nearby & related markers
Cornwall Furnace
Cornwall, PA · est. 1948
Peter Grubb raised this charcoal-fired iron furnace in 1742, tapping the rich ore of the Cornwall hills to smelt pig iron in an age when American industry was still in its infancy. Under later owners—most famously the Coleman family—the works ran for more than 140 years, outlasting nearly every one of its colonial-era rivals. Preserved as a state historic site, it survives as the best intact example of an early Pennsylvania ironmaking plantation.
Cornwall Banks
Cornwall, PA · est. 1947
The Cornwall Banks were among the richest iron deposits in the world and the oldest continuously worked mine in the New World, yielding ore for more than two centuries. From colonial furnaces that helped arm the Revolution to the industrial age, this Lebanon County hillside fed a steady stream of Pennsylvania iron — long described as the greatest such ore body east of Lake Superior.
Grubb's First Forge
Cornwall, PA · est. 1967
Around 1735, Peter Grubb began working iron just north of here, launching an enterprise that would help make Pennsylvania a colonial iron powerhouse. He relied on the Catalan-type forge—a bloomery method with roots in tenth-century Spain—to draw usable iron from ore. Grubb's early efforts seeded the great Cornwall ironworks that followed.
Cornwall Iron Furnace
West Cornwall Township, PA · est. 2005
Founded in 1742 by Peter Grubb beside a rich vein of iron ore and vast charcoal-making forests, Cornwall Iron Furnace grew into a self-sufficient industrial village complete with an ironmaster's mansion and workers' homes. Its furnaces poured pig iron, cast goods, and cannon for the Revolutionary War before passing to Robert Coleman in 1798 and running until 1883. Remarkably, the works survive fully intact nearby — a rare window into early American ironmaking.