Colonie NY, Abandoned AI Tech Steel Plant
These ruins of a steel mill are just outside of Watervliet New York and technically in the town of Colonie. I don't know much about the facility other than that it was closed and abandoned around 2002. Most of it looks like it was built in the 1940s give or take a decade. I suspect that it will be torn down soon. I didn't go inside the fenced area but there wouldn't have been much to stop me had I wanted to go exploring. Wikimapia has an entry for the site and links to some pictures from inside the plant.