historic region in eastern Afghanistan, about 5,000 square miles (13,000 square km) in area and comprising the upper valleys of the Alīngār, Pīch, and Landay Sind rivers and the intervening mountain ranges. Its northern boundary is the main range of the Hindu Kush, its eastern the Pakistani border, its southeastern the Konar (Kunar) Valley, and its western the mountain ranges above the Panjshēr and Nejrāb valleys. The region is mountainous, rainy, and forested.

Nūrestān's regional unity and distinction from the rest of Afghanistan spring from its isolation and the common cultural characteristics shared by its people, who strongly cherish independence, have a clan organization with village governments, and are now settled agriculturists (growing cereals and fruits and raising livestock) living in the valleys. They speak various Kafir languages. The region did not become part of Afghanistan until the 1890s, when ʿAbd ar-Raḥmān, the Afghan emir, conquered it and forcibly converted the inhabitants to Islām. He subsequently changed its name from Kāfiristān (“Land of the Kāfirs,” i.e., infidels) to Nūrestān (“Land of the Enlightened”). The forests of Nūrestān provide most of Afghanistan's timber.