Microsoft has added a new core feature to Power Map called Custom Regions in the May 2015 update of Office 365. The Custom Regions feature allows data to be mapped to the regions that matter most to you, even if they are not the traditional zip code, county, state or country regions.
The Custom Regions feature in Power Map allows you to import KML or SHP files which contain custom polygons. Once imported, you can use custom regions in the same manner as you would use standard regions such as zip codes.
KML files can be created with a variety of free tools which are available on the Internet, you can read more about them here. We also support the import of SHP files, you can read more about the SHP file format here. Note that for SHP files we only support the WGS 84 standard coordinate system projection, more info here.
Custom regions are useful for scenarios involving sales districts, school districts, congressional districts, land lot development, crop rotation, geological analysis, and anything else using custom-defined polygons.
Read more about it here.