A regions consists of one or more base polygons. Regions can be used to represent overlapping features such as animal home ranges, oil spill extents, or the extent of historic wildfire burns. This is a nice feature for analyzing many natural phenomena.
Regions can be discontinuous.
A set of discontinous polygons like all the islands in the Alleutian Chain can be represented as one region. Regions can be nested. Regions allow for faster vector analysis. Since regions are composed of base polygons, questions concerning these polygons can be analyzed much more efficiently compared to storing each region subclass as a separate coverage. Regions are perfect for asking questions concerning intersection, adjacency, and containment.