The Foundry is a location in The Crown & The Flame series. It is the centre of the Technocrats' city. Rumors say that the Technocrats rarely leave the Foundry. They design and develop creative and innovative devices there.
Getting to the Foundry is no easy task as one has to go through a labyrinth which has deadly traps.
In the end of Book 3, Whitlock stated that the city will be under repair when he gets back to the Foundry.