Let's say the land is confined to north America, the size can vary from an entire state to a single zip code (I know zips are logical addressing, not geological, but I have what I have), and the shape is unrestricted so it could be non-convex. I suppose one could convert various kinds of areas (states, cities, boroughs, ...) to lists of zipcodes contained within and OHE them but I feel like that would be the _worst_ solution.