Normandy (in French Normandie) is a region in the northern part of France. People from Normandy are called Normans. The name of Normandy is derived from the settlement and conquest of the territory by the "Northmen" (Northmanni in Latin) or Vikings (Danes and Norwegians) of Hrolf the Walker.
The historic region includes two regions of France: Upper Normandy and Lower Normandy; and also the Channel Islands which are not part of France. It's also famous for cheese. Normandy was not part of France until after the Norman invasion of 1066 so France never invaded England, Normandy did.
It is also famous for being the place that the Allies invaded France through in World War II (See D-Day). During the Battle of Normandy in World War II Normandy became the landing site for the invasion and liberation of Europe from Nazi Germany.
The population of Normandy today is around 3.45 million.