Thanks to both John Komdat and Luke Coletti for suggesting MapBlast, which I was unaware of, and which turned out to be something I can use in many other ways as well. (He says, as he then busily adds to about 60 pages of his website today!)
Bill Thayer Platner's Topographical Dictionary of Ancient Rome <http://www.ukans.edu/history/index/europe/ancient_rome/E/Gazetteer/Periods/Roma n/.Texts/secondary/PLATOP/home.html>