Boston Public Library Central Library (subterranean stacks and archives)

The Boston Public Library's Central Library (Johnson Building) at Copley Square contains multiple below‑grade levels that house closed stacks, special collections, and archival storage. These subterranean spaces were expanded and reconfigured through 20th‑ and 21st‑century renovations to increase compact shelving and preservation facilities. Staff and researchers access many of these collections via internal retrieval rooms and restricted areas beneath the public reading rooms. The underground stack areas are a significant part of the library's collection management infrastructure.