The Pays de Retz (French pronunciation: [pei də ʁɛ]; Breton: Bro-Raez; lit. 'Land of Retz') is a historical subregion of France that currently forms part of the Loire-Atlantique department, but once formed part of the Duchy of Brittany.

The area lies between the southern shore of the Loire estuary and the Marais breton (Breton marshlands), bordered to the west by the Baie de Bourgneuf (Bourgneuf Bay) and on the east by the Lac de Grand-Lieu (Grand-Lieu Lake) and a network of small rivers. Its main towns are Rezé (which was its capital and the see of a Catholic Diocese of Rezé from 510 to 851), Pornic, Paimbœuf and Machecoul (another historical capital city).

History

In the early 9th century the area formed part of Frankish territory, but was coveted by the Breton ruler Nominoe. Nominoe and his son Erispoe won a series of victories over the Franks between 843 and 851, resulting in the Treaty of Angers (851) between Charles the Bald and Erispoe, which gave "Ratense" or Pays de Retz to Brittany.

In subsequent centuries was conflict between Brittany and Anjou over the area. The notorious medieval serial killer Baron Gilles de Rais was from the area and sexually assaulted and tortured a large number of local peasant children before murdering them.

During the War in the Vendée of 1793, the area was a Royalist stronghold.