The Hoenn Region!

The Hoenn region (Japanese: ホウエン地方 Hōen-chihō) is a large region to the southwest of Johto, and resembles the real-world Japanese main island of Kyushu. It is the setting of the Generation III games Pokémon Ruby, Sapphire, and Emerald. The names of most of the cities in Hoenn are made of two words put together (Little Root, Fort Tree, Slate Port, Ever Grande, etc.) rather than colors or plants as Kanto and Johto had done. Professor Birch of Littleroot Town offers the starter Pokémon known as Treecko, Torchic, or Mudkip to Trainers beginning their journey of this vast land.Routes in Hoenn number are numbered as 101-134, breaking the former pattern set up by Kanto and Johto. This is presumably to discourage the idea of being able to travel back to either region after completion of the game, as was done in Generation II and as a mirror of the fact that Japan's road system possesses a similar gap. Some of the routes have differing weather conditions depending on the day they are traveled on.The Hoenn region boasts many dramatic environments from rainforests to deserts. However, its most striking feature is its abundance of water. There are several large islands off the mainland only accessible via water routes, many of which are deep enough for diving. It seems to have a warmer climate than Kanto, Johto, and Sinnoh.
Much of the interior area is forested or mountainous, so most notable cities are found on the coastline. Much of the region is covered in water, almost equal in size as the mainland, restating the theme of the game. People who live in towns and villages in the mountain areas must adapt to the harsh environment. An extreme example of this is the inhabitants of Fortree City, who live in tree houses. This is in stark contrast to other regions in the Pokémon world, as noted by Ruby in Pokémon Adventures, who preferred Johto's many modernized cities to the wilderness and countryside in Hoenn. The center of the Hoenn region includes an active Volcano called Mt. Chimney. The ash from the volcano regularly falls on the nearby towns and routes.
Due to the primarily tropical climate, many of Hoenn's newly discovered Pokémon are rather exotic in appearance, compared to Pokémon from Kanto or Johto.