Several sites (Porte-Joie and Pinterville, for example) have vestiges of ancient habitation. The region was inhabited by three Celtic tribes: the Veliocasses from the Vexin region, the Lexovii from the Lisieux area and the Aulergues (Aulerci) Eburovices. The town of Evreux was Christianised in the 4th century by bishop Saint Taurin, annexed to the Merovingian kingdom by Clovis and became a county in 990.
Throughout the Middle Ages, the land was the stake in many wars between French and Anglo-Norman kingdoms. Philippe Auguste broke up the Plantagenet's lands and annexed Normandy to France after Château-Gaillard was captured in 1204. Later, the Hundred Years' War laid waste to the region.
The 16th century saw the beginning of a period of relative prosperity; churches appeared, towns developed and bridges were built over the Iton. Fortunately the Religious wars and later the Revolution left the region largely unscathed.
Formerly a rural area, industrialisation began in the 19th century with a focus on textile production and metalwork. Evreux (an active core of the Resistance) and Les Andelys were almost entirely destroyed by German and then Allied air raids in the 1940-1944 period. The reconstruction process began over the following years.