Cornwall Furnace
Cornwall, Lebanon County, Pennsylvania
Marker Inscription
Charcoal iron furnace built by Peter Grubb, operated 1742-1883. Best surviving example of the early Pennsylvania ironworks. Now a State historical shrine, gift of Mrs. Margaret Coleman Buckingham, heir of its famous owner, Robert Coleman.
Erected by Pennsylvania Historical and Museum Commission
The Story
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.
Why it matters
Cornwall stands as a rare, tangible link to the charcoal-iron industry that armed the Revolution and laid the groundwork for America's rise as an industrial power.
The story behind this marker
AI contextThe era
In 1742, the ground where this furnace stands was the frontier of a young colony still finding its economic footing. Pennsylvania had rich veins of iron ore, vast forests to burn into charcoal, and limestone for flux — everything the age required to make iron. What it lacked was the finished metal itself, most of which still crossed the Atlantic from Britain at great cost.
That scarcity is what made a place like Cornwall matter. An early ironworks was less a single building than a self-contained world: the furnace itself, the ore pits, the woodlots and colliers who turned timber into fuel, the wagon roads, and the workers' dwellings clustered around the stack. Historians often call these operations "iron plantations," and the name fits — they were rural industrial estates that ran on their own rhythms far from any town.
The timing is the remarkable part. When this furnace was first blown in, the American Revolution was still a generation away and the country that would become the United States did not yet exist. Iron made here helped supply a colony, then a new nation, then a rapidly industrializing century — and it kept doing so until 1883.
People & events
The man who raised the furnace was Peter Grubb, an ironmaster who recognized the value of the local ore and built his works to tap it. To start an ironworks in the 1740s took capital, nerve, and patience; the returns came slowly, and a badly sited furnace could ruin its owner. Grubb's did not fail — it became one of the most durable ironmaking sites in the colony.
In time the operation passed to the Coleman family, and it is Robert Coleman whose name the marker singles out as its "famous owner." Under the Colemans the works prospered enough to become part of one of Pennsylvania's great early fortunes, the kind of wealth built on iron in an age before steel mills and railroads reshaped the industry.
The furnace owes its survival to a single act of generosity. Margaret Coleman Buckingham, an heir to Robert Coleman, gave the site to the Commonwealth so that it might be preserved rather than scrapped or left to crumble. Countless colonial furnaces vanished once their fires went cold; this one endured because a family chose to protect it.
Its place in the American story
Iron is easy to take for granted today, but in the colonial and early national eras it was strategic material — the stuff of tools, nails, stoves, wagon fittings, and the arms and hardware a country needs to defend and build itself. Furnaces like this one helped free America from dependence on imported metal, quietly laying groundwork for the industrial power the nation would later become.
Cornwall is also valued for a simpler reason: it is still here. Very few charcoal-iron furnaces of its era survive in anything like their original form, and this one is regarded as the best-preserved example of its kind. Where most such sites are marked only by a mound or a memory, here the machinery of an entire early-American industry can still be read on the ground.
That makes the place a rare classroom. It lets visitors see, rather than merely imagine, how the country made its first iron — and how that humble, laborious process connects to the larger story of American self-sufficiency and growth.
If you visit
Come expecting industry, not a battlefield or a mansion. The star of the site is the furnace stack itself and the buildings and equipment that surround it — the physical anatomy of how ore, charcoal, and limestone became iron. Take your time reading how the pieces fit together, because the whole point of Cornwall is that so much of it remains legible.
Let yourself picture the noise and heat that are absent now. A working furnace ran day and night for months at a stretch, fed constantly, glowing against the dark, surrounded by the labor of many hands. The quiet you'll find today is the quiet of a fire that finally went out after more than a century.
Set in the rolling country of Lebanon County, it pairs naturally with a slow drive through the surrounding hills that once supplied the ore and the wood. It's the kind of stop that rewards curiosity — a chance to stand inside the origins of American iron rather than just read about them.
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
- · Robert Coleman
- · Margaret Coleman Buckingham
Themes & tags
Nearby & related markers
Cornwall Furnace
Cornwall, PA · est. 1948
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.
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.