The dwarven fortress of Kal'Hirol was long known as a center of learning for the smith caste. Its workshops are where Paragon Hirol conceived his famous improvements to golem resilience and power, and where Hirol's favorite student developed a method for storing refined lyrium that is still used today. These breakthroughs brought Kal'Hirol great prosperity; its passageways are said to have glittered with gold and silver, yet its fall is shrouded in mystery. All that is known of this fortress is that its elite appeared at Orzammar's great doors, exhausted and in despair over the loss of their home.
This section contains spoilers for: Dragon Age: Origins - Awakening.
In the epilogue, it is mentioned that Kal'Hirol is cleared of darkspawn, and eventually the dwarves of Orzammar attempt to reclaim it. House Helmi ultimately leads a host of dwarves to clear the Deep Roads between Orzammar and Kal'Hirol, and though the losses were great, they are ultimately successful. Kal'Hirol is reclaimed by Orzammar once and for all.