Slag Hills

The Slag Hills were a pair of hills made up of slag and rubble just outside the Black Gate of Mordor.

Significance in the Lord of the Rings
The Slag Hills were where the army led by Aragorn made their stand against the armies of Mordor during the Battle of the Morannon. The troops positioned themselves in defense rings on each of the two hills. On each of hills stood a force comprising of Eomer, Imrahil, the Knights of Dol Amroth, and elements of the Tower Guard on the right, and a force comprising of Gandalf, Aragorn, the sons of Elrond, and the Dunedain on the left.