When Iron Was Hot in Loudoun County
In the autumn of 1795, the mining of iron began in Loudoun County, on Catoctin Mountain. A boom industry had dawned, one that would not stop until the Civil War, by which point the county had become Virginia's second-biggest producer of iron.
Even in the midst of a depression, in 1860 the recorded output was 2,250 tons valued at $58,000 -- about $1.2 million today.
When mining began on Catoctin Mountain, across the Potomac River from Point of Rocks, Md., the Virginia Piedmont was being transformed from a wilderness into a prosperous agricultural society. Iron farm implements and wagon-wheel rims were replacing wooden ones. The earliest settlers' homes were decaying, and larger new domiciles needed nails and hardware.
An industrial revolution had taken hold, and it was fed by iron.
The deposits in north-central Loudoun were in the middle of a 120-mile mineral belt extending from an area just west of Baltimore to Frostburg, Md.
The first to exploit this iron-laden area were four men named Johnson. At least three were brothers. One, Thomas Johnson, had been Maryland's first governor and was on the U.S. Supreme Court when he became a partner in Josias Clapham & Co., a consortium made up of Clapham and the four Johnsons.
They had purchased 1,310 Loudoun acres in January 1792, at about $10 an acre -- half the going price of local arable land. Clapham, an astute businessman, lived close by at Chestnut Hill, a still-standing manor house. He had represented Loudoun in most of the Revolutionary War conventions, and had been the county's General Assembly delegate from 1770 to 1788. He was also a director of the Patowmack Canal, which, when finished, was to transport iron ingots to Georgetown and Alexandria seaports.
Another incentive toward creating a county iron industry came in 1794, when Congress authorized the building of federal armories to manufacture firearms. Armories needed iron. At the insistence of President George Washington, an armory was located at Harper's Ferry, at Loudoun County's northwest edge, a few hours' journey by wagon from the Catoctin Mountain iron deposits.
To separate iron from its ore, charcoal provided the heat. Dotting the treed hillsides of Catoctin Mountain were charcoal hearths. In these small ovens, hardwood was partially burned to transform it into charcoal. This light residue was then loaded into sacks and then onto mules, and via "charcoal paths" the docile carriers transported their loads down the slopes to stone-and-brick blast furnaces, where the iron ore was smelted.
The refining operation needed a steady flow of water, both to ensure the furnaces wouldn't overheat and to operate bellows that would blow air through the charcoal bed. That water came from nearby Catoctin Creek.
Near the Potomac, the creek bed looped (see map), and in late winter 1795, Clapham & Co. began digging a tunnel through the loop's isthmus, "500 feet through the rock and 60 feet below the surface of the hill," wrote Yardley Taylor in Joseph Martin's 1835 "Gazetteer of Virginia." As the tunnel's upstream mouth was 15 feet higher than its outlet, the rush of water fed a canal that led to the furnaces. In times of low water, a mill pumped water into the tunnel.
The tunnel openings are no longer visible: About 85 years ago, Sam Fawley closed the ends so his cattle wouldn't wander through during dry times.