By 1967, Norton Furnace was the world’s oldest known operating blast furnace. Norton Iron Works Co. built it in 1873 as an iron shell stack 67 feet high with a maximum inner diameter of 18 feet that burned “stone coal.” It produced 10,502 tons of iron in 1874, and by 1884 its yearly capacity was 20,000 tons. It operated after 1928 under Armco Steel Corp. Kentucky had been a major iron producer since 1791, ranking third in the U.S. in the 1830s and eleventh in 1965. Charcoal timber, native ore, and limestone supplied numerous furnaces in the Hanging Rock, Red River, Between Rivers, Rolling Fork, and Green River regions, where pig iron, utensils, and munitions were made. The old charcoal furnace era ended with depletion of ore and timber and the growth of railroads.