The Iron Building is a historic building at the Watervliet Arsenal in Watervliet, New York. It housed the Watervliet Arsenal Museum until it was closed in fall 2013 for security reasons. The Iron Building was built in 1859 and is "an outstanding example" of pre-fabricated cast iron construction. It is also the only building at the Arsenal to have a strong degree of Italianate styling. The building was designated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers in 1983.