The Wildwoods.

[The map is slapped, upon which the whiteboard swivels again to show its blank side. Ceilto sighs.]

You might not realize this, but we canvass every area you lot stumble across and locate suspicious architecture or cave formations that seem to be promising. The people of Refuge led us to this one - a pre-existing underground edifice that they brushed upon in the course of their own tunneling.