Course of Sauron's Road

The Road of Fire, or Sauron's Road, ran from the Dark Tower’s huge western gate over a deep abyss by a bridge of iron, and ran straight for a league between two smoking chasms, and then to a long sloping causeway up onto the eastern side of Mount Doom, and after encircling the mountain came to the Sammath Naur. The road was constantly repaired by countless slaves. Lava from the mountain was also channelled back to Barad-dûr next to the road in the Naur Trench, filling the gulf around Barad-dûr except for the great Iron Bridge, it was used as a final defence of the Dark Tower, and also to feed the fires for the various engines in the Tower, the Trench ran virtually straight and parallel to the road.