A region's area is determined in several ways, depending on what content is added to the region:
A region can have a simple marker location with no boundary map box; in this way, the map will center on that marked location at a hard-coded zoom level.
If more than two trails are added to a region with specific geographical information, an automatic boundary box will be generated that covers the area of those added trails. Each new trail added will adjust the boundary map box. The map will zoom in to include this boundary box as the viewport. When you edit a region, the automated area will appear as a light blue transparent rectangle.
Sometimes the automated box around the area, along with the zoom level, are not exactly accurate. In this case, the region's area can be customized. When editing a region, you can draw a polygon outline of where you wish the map to be centered. Additionally, you can specify a manual zoom level override.
Note: When editing a region, the polygon outline can be edited, but the boundary box cannot be altered. Subsequently, the marker location of a region will be centered in the boundary map box, unless its manually set.