Record versioning and promotion
Use one of the various techniques for modeling hierarchical data in a relational database.  My preferred approach is visitation numbers (see my answer to this question for more information about visitation numbers) but you could also use adjacency lists.

This will simplify the retrieval of Laws that pertain to a particular Location.

You will also want to include some kind of level indicator on your locations.  This will allow local overrides of broader laws to be identified.  You can sort by the level indicator to pick the most localalized version of any particular law.