The Pentagon is added to the National Register of Historic Places

On July 27, 1988, the Pentagon Office Building Complex was added to the United States National Register of Historic Places, recognizing its historical and architectural significance. Built during World War II, the Pentagon had become a major example of large-scale federal government architecture and a central institution in American military administration. Its five-sided configuration, concentric office rings, extensive corridors, and distinctive exterior reflected the practical and logistical requirements of its original construction. The National Register listing acknowledged the importance of the building's design and its association with the expansion of United States defense infrastructure during the twentieth century. This recognition also placed the Pentagon within the broader national framework for documenting and preserving historically significant American buildings and sites.