Juglans regia,
Persian walnut,
English walnut, or especially in Great Britain,
common walnut, is an
Old World walnut tree species native to the region stretching from the
Balkans eastward to the
Himalayas and southwest China. The largest forests are in
Kyrgyzstan, where trees occur in extensive, nearly pure walnut forests at 1,000–2,000 m altitude—notably at
Arslanbob in
Jalal-Abad Province. It is widely cultivated across Europe.