The Iron Arch is a place inside of Sorrow's Furnace. It is a dark cave southeast of Sorrow's Belly that features one of the entrances into the Forge with three Furnace Guardians guarding it.

The following quests take place in the Iron Arch:

• Fire in the Hole: It is the location of the Flame Djinn.
• Summit Slaves: It is one of five places that must be scouted.
• Tasca's Reprise: It is the location of the group that has Tasca's Map.

Makar Thoughtslayer can always be found underneath the stone bridge in Iron Arch.

Note that the Iron Arch is a landmark inside Sorrow's Furnace, and not a location given on the map.