Discussion: In Bivouac, we have divided North America into a hierarchy of mountain regions. The divisions between the regions are usually rivers and low passes, and all the mountains within a region have one "master" mountain as their parent.
Note that Bivouac also divides North America into "cells". The difference between "regions" and "cells" is that the master peaks of the regions don't have any predefined prominence threshold. Thus we can better balance the area of the regions.
Class: Core definition.