The Millerstown Iron Company was a small anthracite iron company in Lehigh County, Pennsylvania. It was organized under the general incorporation laws of Pennsylvania on April 25, 1873. It constructed the Macungie Furnace, located at Macungie, Pennsylvania, which was blown in for the first time on September 14, 1874. The company could not survive the depression of 1873-1879 and was sold at foreclosure of its first mortgage in 1879. The purchasers reorganized as the Macungie Iron Company and continued to operate the furnace until the onset of the next major depression in 1893. After lying idle for some years, the furnace was sold to a combination, the Empire Steel and Iron Company, around 1900. It was finally sold to the East Penn Foundry company on December 27, 1922, and dismantled.