The Iron Barracks is a part of the fortress, Spearbreakers. It is an above-ground barracks with a stone roof, the walls built primarily out of iron. It has a mess hall and sleeping space for ten soldiers, though at present it only accommodates three members of 1st Squad, 1st company, due to attrition the unit has suffered over time.
The Iron Barracks were designed and commissioned by Splint Spearspin during his second reign. They were built largely with the help of "foreign mercenaries", as they introduced themselves, which were actually Ballpoint's soldiers. See also The Mercenary Incident.