An Iron plantation was a small scale iron production facility common in the Southern United States prior to the 1900s. It involved a process of smelting that produced an inferior grade of iron called pig iron that did not require a large scale industrial process to produce higher grades of iron. Southern states had iron ore deposits that could be used to produce low grade iron in a small plant, or iron plantation.
The old south was geared towards agriculture and did not have the factory structure that was needed to produce larger amounts of high grade iron. This was one of the weaknesses of the confederate army during the American Civil War. Their guns and other equipment was made of low grade iron and not as durable as the equipment used by the union army.