You can add your desired location in the Osclass under Setting’s Locations tab. If the country name is in the Osclass Geo, then all the regions will be imported automatically in the database. If the country is not listed, then you have to add each name of the city, region, and country manually.
It takes too much time if you have too many regions and cities for a specific country. In such cases, you can manually import each region with the cities. Deleting particular region results in the removal of all cities under that region. It is the same for deleting a country name. All the regions, cities, everything under that country will get erased.