The Unova region (Japanese: イッシュ地方 Isshu-chihō) is a region of the Pokémon world. It is the setting of Pokémon Black and White and Pokémon Black 2 and White 2. It is far away from the four other large regions, and the Pokémon which inhabit Unova are diverse and different from those of Kanto, Johto,Hoenn, and Sinnoh. In his director's column, Junichi Masuda suggested that the geographical and social background for Unova draws inspiration from the New York City metropolitan area , although the region features rural locations as well as industrial.
Taken from Bulbapedia