Business in the Hanging Rock region blossomed in the 1850s, making the area Ohio's first chief industrial center. Much of the iron produced there was used to build the nation's growing railroad system, and the railroads in turn carried iron exports from the hills of southeast Ohio to distant markets by way of the Ohio River or the Great Lakes. During the Civil War, Hanging Rock iron makers supplied iron for cannons and other military equipment used by the Union Army, including the iron plate that sheathed the famous iron-clad warship Monitor. Hope Furnace closed in 1874, and the last of the furnaces closed in 1916, but their legacy remained in the stone towers scattered across the landscape of the Hanging Rock Iron Region.