Orodruin
From the fortress's east entrance a road went north then west to the Isenmouthe. Frodo and Sam travelled part of this route on their way south to Mount Doom. A second route "Sauron's Road" went from the west gate of Barad-dûr westwards across Gorgoroth to Mount Doom's "Chambers of Fire." This road ran from Barad-dûr between two smoking chasms and then reached the causeway that led to the mountain. Strachey's "Journeys of Frodo" estimates Mount Doom was probably no more than 10 miles west of Barad-dûr because Sauron's Road from Barad-dûr to the causeway was only a league (about 3 miles) long. From Mount Doom the road went southwest to Minas Morgul.