Army of the West
The Army of the West was the great host prepared by the Lords of Gondor and Rohan to march on the Black Gate after the Battle of the Pelennor Fields. They left Minas Tirith two days after the council of the Last Debate with a force of around 7000 men: 6000 on foot and 1000 on horse.
When the host reached the Cross-roads, the captains stationed a strong force of archers there, to guard against any attack from the East or South. Also left behind were many faint-hearted men who could not approach the Black Gate, and so were commanded to liberate Cair Andros.
The Army of the West fought in the Battle of the Morannon with less than 6000 men total, but because of the destruction of The One Ring, they were able to achieve a very decisive victory. It is not told how many casualties the army suffered.