Taur-im-Duinath was a dark and gloomy forest that extended over a vast area of land in the southern part of East Beleriand. According to The Atlas of Middle-earth, Taur-im-Duinath extended over one-hundred and fifty miles from east to west and possibly two-hundred miles from north to south. Though it is separated from them by the river Gelion, Taur-im-Duinath was part of a great Southern Forest that extended far into Eriador.