Mindeb.

The river Mindeb had its wells in the mountains of Southern Dorthonion and had broken through the Echoriath and Ered Gorgoroth and created the Pass of Anach from where it flowed to the North-Western eaves of Neldoreth dividing Nan-Dungortheb from Dimbar. Mindeb followed the Western eaves of Neldoreth until it met and joined river Sirion in the angle where Forest of Brethil met the forest of Neldoreth. 40 Miles ran Mindeb across the land until it was crossed by the Ancient Road near the eaves and another 40 miles along Neldoreth before the junktion with Sirion.