Matthew B. Gilmore
The National Archives (I) at Pennsylvania Avenue between 7th and 9th Streets NW https://www.archives.gov/dc-metro/washington is a superb public institution for researching Washington DC history. Contrary to perception it is not difficult to use, once you learn how to navigate the catalogs, reading rooms, archivists, and collections.
Besides the building permits (applications) (on microfilm) 1877-1949 the National Archives has paper copies of the Washington DC city directories 1867-1970* in the west reading room on the second floor–available self-service on open shelves.
The National Archives is open M, T, W, Th, F, AND Saturday 9 am to 5 pm.
Published for Washington from 1822 to 1973:
These below are held by the National Archives
The main white pages listing usually includes:
Ceased publication for Washington DC in 1973.
Note: the directory was done by canvas in the December of the year preceding, and one could ask to be excluded (noted as “refused”).
*NARA has microfilm of City directories from across the entire US 1902-1936 Microfilm # Z0001 catalog entry
NOTE: City directories are accessible through Ancestry.com–but only by name, not address.
SEE ALSO House History Resources
**The last directory (1973) is not part of the collection.
FYI: a nice blog post about New York City directories: https://www.nypl.org/blog/2012/06/08/direct-me-1786-history-city-directories-US-NYC