James, I was trying to think if there was a way to do this with the interactive Wikimedia maps. You'd need some way to extract the bounding boxes. If they are stored in OSM or Wikidata it looks like that might be possible programmatically with the current software. [0] Otherwise it looks like a more manual process. :/
I'm afraid I'm not super savvy in this area, but maybe some of this might be helpful?
[0] https://www.mediawiki.org/wiki/Help:Extension:Kartographer#GeoShapes_via_Wik...
Yours, Chris Koerner Community Liaison Wikimedia Foundation