Du Weldenvarden (translated as "The Guarding Forest") was a massive forest that covered Northern Alagaësia. The elven capital of Ellesméra was hidden deep within the forest, as were the ancient elves that inhabited it.
The forest's size was due to the planting spells the elves used. By imbuing their voices with magic, the elves could sing plants into growing into different shapes and patterns. Every house in Ellesméra was sung from a tree.
There were other cities in Du Weldenvarden aside from Ellesméra, such as Osilon, Kirtan, Sílthrim, Ceris, and Nädindel. Arya was captured by Durza, a Shade, in Du Weldenvarden, whilst she was transporting Saphira's egg from the Varden and the dwarves to the elves. The forest was magically protected by elven wards, assuring that nothing could enter its boundaries by arcane means. There were also guards that were posted on the outer edges of the forest.