The Keep on the Borderlands is set in Dyriamarch, a region of Melderyn claimed, but not effectively controlled by that kingdom. There is also a letter meant to be handed to the players before the adventure.
We've been waiting since 1989 for an official release of the Trierzon Regional Module. Since the split between CGI and NRC in 2003, this has looked even more unlikely than it was in the 1990's, but one shouldn't underestimate the power of the dedicated Hârniac! Conal Smith has poured an amazing amount of time into this stunning document.