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Cecil County Life

Principio Furnace

Jan 08, 2015 05:09PM ● By Kerigan Butt

By John Chambless

Staff Writer

Driving through the unpaved pathways through the Principio Furnace site near Perryville on a cold morning last month, Sarah Colenda was tracing not only her family's roots, but revealing the heart of the earliest iron industry in America.

The nation was not yet born when the Principio Company began in Maryland. Back in England, limited reserves of iron ore had been exhausted by centuries of mining and the demands of an era when everything was made of iron. Having found significant deposits of iron ore in the Maryland region, a small team was sent from England in the early 1700s to settle on the sloping banks of the Principio Creek and begin building a forge. The iron slabs produced at the forge were then destined to be shipped back to England.

Principio Furnace was the epitome of high tech when it was built. It was one of the first blast furnaces in North America, strategically located 75 miles from Washington, D.C. It was surrounded by thousands of acres of woodland, which could be cut, transported and burned at Principio to make charcoal, which was then burned in the iron-making process.

“I have pictures of the site where there wasn't a single tree to be seen,” Colenda said. The land was stripped of trees and iron ore to feed the furnace, which was so massive that it operated 24 hours a day. Stopping and starting it was simply too much work, so it never shut down. The first permanent hearth was built in around 1723, and has been lost. Colenda guessed that it might have been where Route 40 now runs.

"The process needed a few things," she said. "They needed water for transportation, and water to run the paddle wheel that operated the bellows in the furnace. They had to melt the iron ore and pour it out into molds. Then it had to go from the furnace to the forge, where it was reshaped again."

Principio was a busy place, turning out half of the iron shipped to England between 1718 and 1755 – about 25,000 tons. The slabs of iron produced at Principio were called “pigs,” because, when stacked next to each other, they looked like pigs lying on their sides. The pig iron sold at the furnace cost 10 pounds per ton in 1727, and bar iron was valued at 35 pounds per ton.

The work was back-breaking, with iron ore arriving by boat from an auxiliary site near Fort McHenry in Baltimore. In the 1700s, a small bay allowed boats to dock at Principio, deliver ore, and then load up the iron pigs for shipment back to England. The water, long since cut off by a railroad embankment, is gone.

A self-sufficient community sprang up around the furnace, with housing for workers, a school, a post office, a store, machine shop and more. Perryville was a short horse ride away, but Principio was able to function pretty much on its own.

The ore was unloaded from boats and pulled by horse-drawn wagons to the nearby furnace. In the earliest days of Principio, slaves were required to do much of the work, although there were skilled apprentices and craftsmen at the site to manage the process. The smoke from the charcoal burner, the searing heat and roar of the furnace, and the mountains of “slag,” the molten byproduct of making iron, made the Principio site fairly hellish.  Sycamore trees were planted to help absorb the soot, and generations of sycamores still dot the property.

Today, Colenda said with a laugh, “we've got a whole lot of slag.” Scraping away a thin layer of soil with one foot, she struck a chunk of the gray-green, glass-like substance. “It's everywhere,” she said. With practically no useful purpose – it was once used only as a base for road paving – the slag is up to six feet deep at the Principio site.

That, and the fact that the site has been preserved but not restored, means that the Principio Furnace complex is off-limits to visitors. “There are holes everywhere,” Colenda said, although she credits teams of volunteer workers who cut back the encroaching brush at the site in the summer, revealing more history every year. In a way, the thick vines and undergrowth actually protected the site from vandalism during the decades when it sat idle.

The Principio Furnace was destroyed twice by British troops, since it was a source of cannons and cannon balls used in the Revolutionary War and the War of 1812. A third furnace was built in 1836, and the base of it remains standing today. It was a revolutionary design, using a hot-air exchange system. It operated until 1894. A fourth furnace was constructed in 1890, but when production ended after World War 1, it was dismantled and shipped to a site in West Virginia, Colenda said.

After the original owners, the property passed to the Whitaker family, who owned it from the early 1800s until 1981, Colenda said. From 1981 to now, it has been owned by the Stewart family. Principio stopped production in the late 1920s. Colenda's grandfather was a resident manager of the property, and came to the site in 1930 to work for the Whitaker family. Her father took over part of the property, working as a farmer and selling sand and gravel, as well as timber. Colenda lived with her parents in the 1836 Mansion House across Route 7 from the furnace site, so Principio has been part of her entire life, except for four years when she lived elsewhere with her husband.

“The mansion has gone through several renovations," she said. "It was the Mansion House Inn in the 1930s. It was a rental property, and eventually my mother and father and I moved into it in 1958. My father worked for the Whitaker family from the time he was 12 until 1981. When the Stewart company purchased it, I went to work running a Christmas tree business for them. As we unearthed the history, I became their director of the foundation. So there are two families and a lot of history. The Stewarts have done a great job of preserving the history of this wonderful place.”

Colenda said the Principio site “is near and dear to my heart.” Its preservation is supported financially by the Stewart family. The Mansion House is the site of occasional meetings and special events, and the furnace site can be toured by special arrangement.

Keeping the site alive in a converted wagon shed on the furnace property, Matt Harris and his father run the Harris Metalsmith Studio, which turns out custom iron gates and accessories, along with sculptures, including one installed at the Dansko distribution center in West Grove, Pa.

What makes the Principio site so special, Colenda said, “is that every building is original. We know its history. It's stayed in two families. It's been preserved, but not totally restored. It's my hope that one day we can further the educational opportunities here.”

Colenda hopes that the site may eventually be part of a walking and biking trail system. The former Pennsylvania Railroad bed is still visible on the land, including two high embankments that used to be either end of a railroad bridge. Colenda envisions a regional trail system and historical markers that will let visitors learn about the Principio property.

As a mainstay of the organization that oversees the 200-acre site, “I grew up in the house, so I get to come home to work every day,” Colenda said with a smile. “It's pretty nice to be able to say that I love what I do.”

Free, private tours can be arranged by calling 410-642-9213.

To contact Staff Writer John Chambless, e-mail

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