Within 1,800 square miles of the lower coal measures that became known as the Hanging Rock Region, 100 iron-producing blast furnaces were built to meet the needs of early settlers, then to furnish ordnance for a nation at war, and finally to supply merchant iron to the steel mills. Lawrence County, centrally located within the region, had 23 blast furnaces constructed between 1826 and 1909: Union, Pine Grove, Aetna, Vesuvius, Buckhorn, Mt. Vernon, Hecla, Lawrence, La Grange, Centre, Olive, Washington, Oak Ridge, Pioneer, Monitor, Belfont, Grant, Etna-Alice, Etna-Blanche, Maggie, Sarah, Hamilton, and Ironton.