Catoctin Iron Furnace in Frederick County, Maryland

For over a century, the Catoctin Iron Furnace smelted iron, its forges spewing smoke and burning red hot. In the eighteenth and nineteenth centuries, it fueled the machines of war. Much of this backbreaking work was done by slaves.

Catoctin Iron Furnace is a historic iron forge along U.S. Route 15 from Frederick to Thurmont in Frederick County, Maryland. Though forges were present when the ironworks were operational, there is currently no forge at the site. But you can still tour the grounds and the ruins of the “Isabella forge” casting shed and the owner’s mansion.

In 1774, four brothers: Thomas, Baker, Roger, and James Johnson, built Catoctin Furnace to manufacture pig iron from locally-mined hematite. The oven produced cannonballs for the Continental Army during the American Revolutionary War, including shells fired during Yorktown’s siege. Some claim it also provided cannon and produced plates for the USS Monitor during the Civil War, but researchers consider that improbable.

On the eve of the American Revolution, the Johnson brothers eyed the Monocacy River Valley’s industrial potential. They acquired land under Catoctin Ridge and erected an iron furnace. The original Johnson Oven burned until 1776, producing useful tools and household products including the famous “Catoctin Stove,” also called the “Ten Plate Stove” and the “Franklin Stove”.