Battle of Azanulbizar:

The final battle in the war of the Dwarves and the Orcs, in which the Dwarves, in return for an insult done to the body of Thror, pursued an extermination policy against the orcs. In this final battle the Dwarves had the victory, though with great loss. Thanks to this battle, the Orc population was diminished for many years, allowing safer travel. However, the orc population had grown back to normal by the time of the War of the Ring.