Administratively, Normandy is divided into five départements: Calvados, Eure, Manche, Orne, and Seine-Maritime. It covers 30,627 square kilometres (11,825 sq mi), comprising roughly 5% of the territory of metropolitan France. Its population of 3.37 million accounts for around 5% of the population of France. Normans is the name given to the inhabitants of Normandy, and the region is the homeland of the Norman language.
The historical region of Normandy comprised the present-day region of Normandy, as well as small areas now part of the départements of Mayenne and Sarthe. The Channel Islands (French: Îles Anglo-Normandes) are also historically part of Normandy; they cover 194 km² and comprise two bailiwicks: Guernsey and Jersey, which are British Crown dependencies over which Queen Elizabeth II reigns as Duke of Normandy.
Normandy's name comes from the settlement of the territory by mainly Danish and Norwegian Vikings ("Northmen") from the 9th century, and confirmed by treaty in the 10th century between King Charles III of France and the Viking jarl Rollo. For a century and a half following the Norman conquest of England in 1066, Normandy and England were linked by Norman and Frankish rulers.
Celts (also known as Belgae and Gauls) invaded Normandy in successive waves from the 4th to the 3rd century BC. When Julius Caesar invaded Gaul, there were nine different Celtic tribes living in Normandy. The Romanisation of Normandy was achieved by the usual methods: Roman roads and a policy of urbanisation. Classicists have knowledge of many Gallo-Roman villas in Normandy.