The Wold
From Tolkien Gateway
The Wold was the northernmost and least populated part of Rohan, lying between Fangorn Forest and the River Anduin, and bounded to the north by the River Limlight.
During the War of te Ring, the third assault wave by Dol Guldur on Lorien was driven into 'the Wold, where the Ents from Fangorn Forest met them and destroyed the them.