Dear Mr. McKenzie,
Thank you for posting your request on History Hub!
According to Americans Overseas in U.S. Censuses (Bureau of Census Technical Paper 62, 1993) by Karen M. Mills, page 3, “... a 1950 census report stated that in the 1940 census, the War and Navy Departments provided the Census Bureau with the number of their personnel stationed abroad, and the State Department furnished counts of Americans in the diplomatic service abroad and their dependents living with them.”
Regardless of whatever information was collected for persons in places other than U.S. territories and possessions (listed below), it was not retained and it is not in the National Archives custody. Such information appears to have been collected for informational or statistical purposes only.
For 1940, there are census schedules for the Canal Zone, Alaska, Hawaii, Guam, American Samoa, Puerto Rico, and the U.S. Virgin Islands.
We searched the National Archives Catalog and located the series Population Schedules for the 1940 Census and the series Enumeration District and Related Maps, 1880-1990 in the Records of the Bureau of the Census (Record Group 29) that might be of interest to you. Most of these records have been digitized and may be viewed online via the Catalog. You may contact the National Archives at Washington, DC - Textual Reference (RDT1) at email@example.com for assistance with the population schedules and the National Archives at College Park - Cartographic (RDSC) at firstname.lastname@example.org with questions about the enumeration maps.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from RDT1 or RDSC. We apologize for this inconvenience and appreciate your understanding and patience.
We hope this information is helpful. Best of luck with your research!
[Some information provided by Claire Kluskins, Subject Matter Expert]