A small river which ran through the Old Forest, east of the Shire lands.

The Withywindle's source was from the Barrowland hills, and it ran down the Old Forest and met with the Brandywine River. In its valley, called Dingle, dwelt the formidable tree-spirit, Old Man Willow.

The River-Woman, the spirit-being of the Withywindle, had a daughter called Goldberry the River-daughter, whose spouse was Tom Bombadil, Master of the Old Forest.