William and Mordecai Miller and John Irwin organized Nelson Furnace in 1836. The blast furnace had two forty-foot pyramidal stone stacks with six-foot hearths, and its iron output in 1857 was 12 tons daily. The Civil War boom in iron brought a merger with Belmont Furnace in Bullitt County in 1865, and after nine years Nelson and Belmont furnace closed in 1874. 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 material for numerous furnaces making pig iron, utensils, and munitions in the Hanging Rock, Red River, Between Rivers, Rolling Fork, and Green River regions. The old charcoal furnace era ended with the depletion of ore and timber and the growth of railroads.