The Grand Duchy of Karameikos was the location of many old school D&D campaigns. The later B-Series modules for Dungeons & Dragons were located there. By 1994, the metaplot had promoted the Grand Duchy to a Kingdom, as seen in the Karameikos: Kingdom of Adventure box set.
Back in the Grand Duchy years, we had some maps of the area in the D&D Expert set (1980) and GAZ1 (1987).
These maps are small. The Kingdom of Adventure maps magnify the area into large scale!
One could – and many have! – run an entire D&D campaign here, start to finish.
“The Known World” later acquired the official name of Mystara, and the setting would be shared between D&D and AD&D.
Karameikos: Kingdom of Adventure [BOX SET]
1994 … Jeff Grubb & Aaron Allston & Thomas M. Reid … TSR 2500 … ISBN 1560768533
* Explorer’s Guide (128 pages)
* Adventure Book (32 page)
* interactive audio CD
* 2 poster maps
* 12 parchment maps, illustrations, and player props
* 8 hero cards
Noble Knight Games | DriveThruRPG (PDF / Reprint)
This set is now in the collectible realm. However, an enterprising DM could buy the PDF ($10) and print the map sections, stitching them together electronically or manually.
The Known World (TSR 2500XXX0702)
Threshold is a great home base for beginning adventurers. They can move on to the capital city Mirros later.
Kingdom of Karameikos (TSR 2500XXX0701)
I’m not well-informed about late-era Known World, but I did notice that Alfheim is now the Ruined Forest of Aengmor. Castellan Keep is where the famous Keep on the Borderlands is often placed by DMs. The capital city of Mirros, I remember better as Specularum.
Vaults of Pandius. More Mystara source material and adventures than a DM could fit into one campaign!