Sinnoh is a region in the Pokémon series and has is the main region in fourth generation of games. So far, it is larger than any other region in the series. The enormity of the region rises even more if you include the very large underground area. The area itself is based on the upper part of the real life Hokkaido region. In all, there are fourteen cities and towns, and a copious amount of other areas as well. There are thirty routes, and three large lakes (each one featuring a legendary Pokémon).