We support the same countries as Google. If your country does not appear in the region drop down, you can add a country column in the data and make sure the country drop-down is using that.
Google maps supports the countries found on their mapcoverage page.
The region option gives a preference to a certain region when doing an address lookup. For example when looking up Toledo with the region set to Spain the result on the map should be Toledo, Spain. However, when the region is set to United States for Toledo the result should be the coordinates for Toledo, Ohio. Explicitly having data with the country and setting the Country drop down helps to ensure better accuracy, especially for zip codes.
Region drop down and Country drop down