One or more ONIX codes identifying regions included in the territory. A region is an area which is not a country, but which is precisely defined in geographical terms, eg World, Northern Ireland, Australian Capital Territory. Successive codes must be separated by spaces. Optional and non-repeating, but either <CountriesIncluded> or <RegionsIncluded> is mandatory in each occurrence of the <Territory> composite.

Note that if used, the ‘WORLD’ region code cannot be combined with other region codes.