Here's the Freeport Forge (West Freeport):
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(There's a regular forge by the door that leads into this little area behind the arena. Find the entrance ramp to the arena and then follow the outside wall to the left until you see a building with a wooden door. Go into the building and follow the left hallway to a second wooden door. That should get you to the forges.)
Here's the Royal Qeynos Forge (South Qeynos):
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The one by Armor by Ithkar is a regular forge, I've discovered. None of the human cultural forges are called Antonican Forge. The one that should be used for any recipes that call for the Antonican forge is the Royal Qeynos Forge.
(Seafarers' Ringmail and Field Plate armors are made in Freeport, while Full Plate and Antonian items are made in Qeynos.)