Undertown is a fictional city-state in Paul Stewart's series of books, The Edge Chronicles. It was founded when the many different species throughout the Edge migrated to form a town underneath the great floating city of Sanctaphrax. The central ethos of the city was that every undertowner was free, to live as he saw best without compulsion or coercion. It is the economic centre of the edgeworld.[1]
In the Quint and Twig trilogies, Undertown is ruled by the United Leagues of Undertown Free Merchants, powerful trading organizations that monopolize the economy of the Edge. The Leagues disband at the end of the First Age of Flight, when stone-sickness renders their ships unusable. In the first two books of the Rook trilogy, Undertown is ruled by the Hammerhead Goblins, who enslave the populace. In the last book of the Rook trilogy, Undertown no longer exists, having been destroyed by a Dark Maelstrom. However, the city of New Undertown - dedicated to the principles of democracy and equality on which Old Undertown was originally founded - has been founded in the Free Glades.