While searching for locations for Army Post Offices (APOs) for my own research I came across these sites. In case the embedded link does not work, I provided the actually link to be copied and pasted. #1) I came across this link. This website provides a few tips that explains some common discrepancies. http://www.7tharmddiv.org/docrep/Location of APOs 1942-1947.pdf #2) Here is another location of the same document just on the Archive.org website. Here <--- This link may be difficult to reach depending on your firewall and router settings. Numerical listing of APO's, January 1942 - November 1947 : United States. Adjutant-General's Office : Free Download & Streaming : Internet Archive Unfortunately, the file is too large to upload into the forum, so the links will have to suffice. Both locations should allow you to download the document to your computer.
Here is another awesome PDF I found that would be helpful for any trying to trace mail of loved ones. APOs in Egypt during WWII. https://www.kelleherauctions.com/specials/exhibit_wilson_5.pdf
@astreb Incredibly useful info for those who are looking for these, thanks. Immediate thoughts to HyperWar and WW2.org as places to house this info.