Inside 'The Underground'

Inside a former limestone mine in northern Butler County, Iron Mountain’s site serves as a secure storage facility, housing data centers, physical and digital media, documents and more.

The site was formerly owned by U.S. Steel and used to supply limestone to steel mills from 1902-1952. It sits 220 feet underground, offering protection from the elements and natural disasters. With more than 6 miles of roads and 1.8 million square feet of developed space, the facility is climate controlled, maintaining a temperature between 53 and 55 degrees with the help of a 100-acre underground lake.