Standardized de-identification of sub-national regions

I was wondering if the issue of de-identification of state/province/county level data has arisen at all? There are a few ways to handle this, and having an ontology define some of these as standards would be an interesting way to go. E.g. enabling state level data to be grouped more generally into categories like "Western USA", "Eastern seaboard, USA", etc. ; Or european countries to be associated with a "Europe" grouping.