Potomac Annex, District of Columbia

The Department of State, headquartered across the street, recently took over this leafy and historic 12 acre site, also known as Potomac Hill, and Navy Hill. This was the location of the original Naval Observatory, which operated from 1844 to 1893, when the new Naval Observatory site opened, two miles north of here. The Navy continued to use this site, which has a dozen old and historic buildings on it, primarily as a hospital, until 1942. During World War Two, this campus became the Washington headquarters and principal research laboratory for the OSS (the Office of Strategic Services), which after the war became the CIA, and continued to use the site for some time. The historical importance of the OSS, and the fact that this may be the birthplace of the CIA, is not generally acknowledged. The State Department’s current use of the site is also bit mysterious.