Lower Normandy (; Norman: Basse-Normaundie) is an administrative region of France. It was created in 1956, when the Normandy region was divided into Lower Normandy and Upper Normandy. The region includes three departments, Calvados, Manche and Orne, that cover the part of Normandy traditionally termed "Lower Normandy" lying west of the Dives River, the Pays d'Auge (except a small part remaining in Upper Normandy), a small part of the Pays d'Ouche (the main part remaining in Upper Normandy), the Norman Perche and part of the "French" Perche. It covers 10,857 km2, 3.2 percent of the surface area of France.
The traditional province of Normandy, with an integral history reaching back to the 10th century, was divided in 1957 into two regions: Lower Normandy and Upper Normandy.
During the Roman era, the region was divided into several different city-states. That of Vieux was excavated in the 17th century, revealing numerous structures and vestiges bearing testimony to the prosperity of the Caen region.
The region was conquered by the Franks in the 5th century.
In the 9th century, the Norman conquests devastated the region. Much of the territory of Lower Normandy was added to the Duchy of Normandy in the 10th century.
The victory of Tinchebray in 1106 gave Normandy to the kings of England again. Nearly one hundred years later, in 1204, King Philip II Augustus of France conquered the region, apart from the Channel Islands. Then, during the Hundred Years' War, it was regained by the Plantagenets. However, the French recovered the mainland part of the region between 1436 and 1450. By 1453, the French monarchy controlled much of modern France apart from Calais, which remained in English hands.
During the Second World War, the main thrust of Operation Overlord was focussed on Lower Normandy. The beaches of Calvados were the site of the D-Day landings in June 1944. Lower Normandy suffered badly during the War, with many of its towns and villages being destroyed or badly damaged during the Battle of Normandy.