The Hollow Marches

The ruin-country: a broad belt of collapsed halls, choked orchards gone feral, road-traces, and boundary stones with names on them that appear in no Kingdom record. Whatever stood here was Faerie work and it was extensive.

The Marches are the strongest evidence that the Kingdom is a successor to something larger, and the court's flat refusal to investigate them is itself worth a campaign.

Geography

Broken stonework under two or three centuries of growth, distributed too evenly to be a single city and too densely to be anything but continuous settlement. The boundary stones are the worst part: they are legible, they are in a recognizable hand, and the names are of nowhere.

The Witnesses

Boggarts live in the ruins, one to a holding, and are the only living witnesses to any of it — except that boggarts, like all fey, lost their memories at metamorphosis, and what they have instead are habits: sweeping a hall that has no roof, keeping a gate in a wall that has no other side.

A great deal could be reconstructed from watching them, if anyone thought their behavior worth watching.

Relations

None. The Marches are avoided by the Wilds and denied by the Kingdom, which is the only subject on which the two governments have ever fully agreed.