Sinnoh is the region where the "Diamond and Pearl" series takes place.
The Sinnoh Region is a Region with rare and Valuable Pokemon, it is home the the media city of the World in Jubalife city. This Region is home to Professer Rowan, The offical Authority on Pokemon evolution.
Town and Cities of Sinnoh
Twinleaf town. It is a small but very quaint city it is the city in which Dawn is from.
Sangem town. This city is on the edge of a beach, professor rowan's lab is located here, this is where Ash and Dawn met.
Jubalife City. This is the Media Center if the world, there is a huge television broadcast station as well as the GTS.
Oregburg city. This town is located over Mt.Cornet, this town is rich for mining and Digging, The Gym Leader uses Rock Pokemon.
Eterna city. Eterna city is also right over Mt. Cornet, this city is home to Amity Park, and the Eterna city Pokemon gym the leader uses Bug Pokemon.
Solaceon town. doesn't have a Gym but it holds the Day care center and the Solaceon ruins Where Unown appears.
florama Town. This town is full of Meadows and Flowers.
Hearthrome city, this City holds the pokemon contest as-well a gym that uses ghost Pokemon.
Pastoria City, This City holds the Safari zone and a gym. The leader Uses Water Pokemon
Celestic town, it is believed to be the first town created in Sinnoh
Veilstone city- the Home town of Team Galactic, and a fighting Gym
Snowpoint city, this is the only city in all the pokemon towns where it snows, The leader uses ICe pokemon
Sunyshore city, a city ran on nothing but solar panels, the gym leader uses thunder Pokemon