"The edges of a city's defined borders don't really mean all that much when they bleed into yet more urbanity." – Nate Berg
The short version
Metropolitan areas for the Where On Earth (WOE) hierarchy derived from Natural Earth (NE) urban areas. Read: Polygons
This is very much a work in progress.
The longer version
I still need to write it.
A word about Github
In the long-run Github may not be the best venue for managing all of these records. But it's not an entirely crazy idea either so we're going to try it for a while because it's easy and safe.
Reverse geocode all the edges of the geometries for each record to at least the country level, if not state. As of this writing there is a hierarchy of places (state, country) for each record based on their geometry's centroid.
Figure out the list of children for each record.
Try to work out place names for each (some?) record.