| This article contains fan speculation.|
There is no solid evidence for or against some parts of this article.
According to the anime novelizations, the capital of this nation is Tōkyo City, though this capital has not been mentioned in any other medium. The political body residing in this capital is unknown as well.
The main evidence to support the fact that the main regions of the Pokémon world are a part of one nation is their mutual use of the term "National Pokédex". The National Pokédex is a Pokédex listing that all main regions share, which begins with the starter Pokémon of Kanto, and has reached its end so far with a 649th member, Genesect. Each region also has its own regional Pokédex, consisting of a local variation on the numerical order, which typically does not include all Pokémon introduced up to that generation (the New Pokédex in Generation II being an exception, as it included all 251 Pokémon included in that generation). Regional Pokédexes always begin with starter Pokémon of that region, (With the exception of Unova's, which starts with Victini) rather than Kanto's as with the National Pokédex.
Subnational divisions are known as regions, each with their own similarities and differences. The following is a list of known regions confirmed to be part of the Pokémon nation, as they all use the same National Pokédex listing.
Due to the fact that these regions are said to be farther away from the others, some of them have a completely different theme, and both Orre and Unova are based on areas outside of Japan (the basis of the rest of the nation), it is unknown whether or not they are part of the same nation. Just the same, Pokémon are ordered in their own systems in each region, and there is no mention of the National Pokédex order at all.
These regions are featured in the Pokémon Ranger Games, and reference the Ranger Union, a nation-like entity.