Thomas Willcox first appears in public document of Concord in1725. He leased water rights on the West Branch in 1727, and purchased land for a mill in 1729. During the 18th Century, the Willcox Paper Mill produced pasteboard, sandpaper grade paper, and commercial grade. The commercial grade was used for currency and other government issue in several colonies, and in such noteworthy institutions as Benjamin Franklin’s printing shop.
The Ivy Mill also produced the paper for United States currency issued during the Revolution and the Federal period, and Willcox’s company is credited with inventing the fiber-inlaid paper which made subsequent currency very difficult to counterfeit.
In 1727 Thomas Willcox married Elizabeth Cole, an Irish Catholic. Shortly after, the Willcox home became site of Catholic services, evolving into the first Roman Catholic parish in Pennsylvania.
James Mark Willcox, the sixth member of the family to head the milling business, closed and razed the old mill, replacing it with a “modern” stone structure in 1829, exactly a century after the founding. That mill made paper until shortly after the civil war, when it was replaced by larger facilities in the nearby settlement at Glen Mills.
Descendants of the original builder retain the old mill ruin and the house which contained St. Mary’s Chapel, site of Catholic worship until St. Thomas Church was finished in 1856.