USER:JENGOD RESEARCH AND REFERENCE BOOKMARKS

Link to HathiTrust version of free ebooks when available (better UI esp on mobile, individual pages are downloadable, etc.)

Bloomberg Professional Services
British Newspaper Archive (Irish papers as well; subs avail via Wikipedia Library)
Lexis-Nexis
Newspapers.com (subs avail via Wikipedia Library)
NewspaperArchive.com, potato-quality microfilm scans of smaller/different papers than Newspapers.com (subs avail via Wikipedia Library)
ProQuest

U.S. history sources

The Civil War was not the chivalrous contest that white American prefers to remember.
— Black flag over Dixie (2004)

NYC Digital Vital Records
Perry Castañeda Library US Topo 1887–1945 & US Topo 250k broad view
NARA: Post Office Reports of Site Locations, 1837–1950 🕵️ 🏅
USGS National Map Download Client
familysearch.org ( registration required) 🕵️ 🏅
For oldest state prisons mostly likely to hold records of those convicted of ancient crimes: Lists of United States state prisons
Who's who of the Colored Race: A General Biographical Dictionary of Men and Women of African Descent ; Vol. 1. (1915). United States: (n.p.).
WWII: amphibious assaults have unlinked air-war articles, airfields should probably mention relevant ground campaigns etc.
Domestic conflict: Indian war? There's probably a nearby historic railroad stub that has no idea it was involved.
Railway Guides