The Valley Iron Works was one of eight local rolling mills that helped to make the Coatesville area a center of boiler plate production in the mid eighteen hundreds. The mill operated, with a few interruptions, for over eighty years, from the late 1830’s until it was dismantled in 1919. It reached its pinnacle of prosperity in the 1870’s and 1880’s under the management of Charles and Joseph Pennock. It employed 200 men, boasted the largest plate mill in the state, and supplied wide iron plates for the thriving locomotive building industry in Philadelphia and the fledging shipyards constructing iron hulled vessels that flourished along the Delaware River from Wilmington to Philadelphia. Two of its most important contributions was supplying iron plates for the City of Peking, the largest American steamship ever built, and for the USS Dauphin, one of the first iron hulled ships of the US Navy.ourt