The Drâa is the longest wadi in Morocco, draining the southern slopes of the High Atlas into the Sahara along a course of more than a thousand kilometres. The conventional Drâa Valley designates the upper, palm-lined section of some two hundred kilometres between the Mansour Eddahbi reservoir near Ouarzazate and the dunes of M'hamid el Ghizlane.
The valley is the most concentrated landscape of southern Moroccan ksour and kasbahs in the country: more than three hundred earthen fortified villages, organised in six distinct palm-grove sections (Mezguita, Tinzouline, Ternata, Fezouata, Ktaoua, M'hamid), each formerly governed by tribal-confederation councils. The architectural register of the Drâa is the principal subject of Moroccan earthen-heritage scholarship.
The valley has been a corridor of trans-Saharan trade since at least the Almoravid period, with the merchant caravans of Sijilmasa and the southern oases passing along its course toward Marrakesh. Its population is a layered mix of Berber (predominantly Aït Atta and other Tachelhit-speaking groups), haratin (settled Saharan oasis cultivators), Arabophone, and Jewish communities, the last largely emigrated to Israel after 1948.
Contemporary pressures on the valley combine prolonged drought, the silting of the Mansour Eddahbi reservoir, and outmigration to coastal cities. Conservation efforts at individual ksar and kasbah sites — including those of Tamnougalt, Aït Ben Haddou (just outside the valley proper), and Skoura — are documented at length by the sister archive at ksour.org.