In the 1640s, every nail, horseshoe, cooking pot, and tool in the American colonies had to be imported from England -- a two-month voyage that made iron goods prohibitively expensive. John Winthrop the Younger saw an opportunity. The colonies had abundant forests for charcoal, rivers for power, and bog ore for raw material. In 1641, he sailed to England to raise capital, and he returned with enough backing to break the colonies' dependence on imported iron. Winthrop first built a furnace in Braintree, Massachusetts (now Quincy), completing it in 1645. But when ironmaster Richard Leader arrived from England, he scouted a better location: the Saugus River, which was navigable for shallow-draft vessels, could be dammed for waterpower, and sat amid forests and bogs rich in raw materials. On October 15, 1645, Winthrop secured from the Massachusetts General Court a 21-year monopoly on iron production and an exemption from taxes. Hammersmith began operations in 1646.

The Saugus works was a complete production chain under one operation. The blast furnace smelted bog ore into pig iron and gray iron, the latter poured directly into molds for firebacks, pots, pans, kettles, and skillets. In the forge, pig iron was refined into wrought iron under a 500-pound trip hammer that pounded it into merchant bars, which blacksmiths across New England shaped into finished goods. The rolling and slitting mill flattened iron into stock for nails, bolts, horseshoes, wagon tires, axes, and saw blades. Seven large waterwheels powered the entire operation, some rigged in tandem through huge wooden gears. One critical problem nearly stopped the project: limestone, the standard flux used to separate impurities during smelting, was unavailable locally. Through trial and error, the ironworkers discovered that gabbro -- a dense igneous rock mined in nearby Nahant -- could serve the same purpose. It was an improvisation born of necessity that kept the furnace burning.

Running North America's most advanced ironworks required specialized knowledge that most colonists lacked. Skilled ironworkers were recruited from England, but the less experienced local men who joined the workforce met with frequent and sometimes fatal accidents around the furnaces and heavy machinery. Among the laborers were Scottish prisoners of war, captured during Oliver Cromwell's campaigns and transported to the colonies. These Scots performed the grueling unskilled work -- chopping wood, hauling materials -- though some eventually learned trades like charcoal-making, blacksmithing, and carpentry. A wharf on the Saugus River loaded finished iron onto ocean-going vessels bound for ports along the New England and Chesapeake coasts. The ironworks operated for roughly 24 years before closing around 1670, and the site gradually disappeared beneath underbrush and centuries of accumulated earth.

In 1898, the Lynn Historical Society placed a marker near the forgotten site, noting that Joseph Jenckes had 'made the dies for the first silver money coined in New England' here and built 'the first fire engine in America' in 1654. The plaque itself soon vanished under vegetation. The site's modern rescue began in 1915, when antiquarian Wallace Nutting purchased a 1680s farmhouse believed to have been the ironmaster's home and restored it as 'Broadhearth.' But the turning point came in 1948, when archaeologist Roland W. Robbins -- the man who had found Thoreau's cabin at Walden Pond -- began excavating. Robbins unearthed the foundations of the blast furnace, the forge, holding ponds, and a canal. He recovered the original 500-pound trip hammer and a waterwheel that had powered the bellows. Biologists from Harvard University developed a special process to preserve the waterwheel's ancient wood. Experts from MIT, the Smithsonian, and Harvard's botanical museum all contributed to the restoration.

On April 5, 1968, the site joined the National Park Service as the Saugus Iron Works National Historic Site. Today, visitors can walk through reconstructed versions of the blast furnace, forge, and rolling mill, all standing on or near their original foundations along the Saugus River. The quarter-ton trip hammer, the wooden gears, and the waterwheel mechanism demonstrate the scale of 17th-century industrial ambition. The restored 17th-century house anchors the site, a domestic counterpoint to the heavy industry that once surrounded it. From above, the Saugus River bends through what is now suburban Boston, and the reconstructed timber buildings sit surprisingly small against the surrounding neighborhoods. But this compact site represents something enormous: the place where North America's industrial history began, where colonists first transformed raw ore into the nails, tools, and hardware that built a new world. The park is open seasonally from spring through fall, ten miles northeast of downtown Boston.