I don't think that really answered his question, or at least the first part. He is looking for some definitive map of the political geography of Erebus. Unfortunately, that doesn't really exist. Kael has chosen to leave most of the geography up to the player, but we do know a few things.
As of the 300th year of the age of rebirth the Bannor Empire was the largest in the world. Decius may have established a larger one for himself though, led mostly by his Calabim troops. Cardith's young empire is quickly growing too, and may surpass the sze of these, but the populated areas are not so widespread.
From Valledia's entry we see that the Amurites share a coastal boarder with the Infernal. The Bannor and Lanun are also close enough for the Infernal to invade them, but the Amurites are weaker so they are a better target. Presumably the Elohim also share an infernal boarder, but as they were winnign against the demons they signed a peace treaty that the Infernals will not break (but Ethne eventually will, when she summons Basium).
The Hippus lands are surrounded by those of the Amurites, Kuriotates, and Elohim. However, as mercenaries they can be found almost anywhere. While you would expect a nation of horse riders to come from a flat area, all their lands mentioned are hills where their sheep graze. The Hippus are in fact masters of animal husbandry of many kinds.
Most of the Khazad still live underground, but those aren't really relevant to the game. Those above the surface live near the Deruptus Pass.
Before Decius joined them, the Calabim preferred to keep only a small kingdom on the edge of the desert of Myrh, so they could better protect their secret. Decius (if he joined them) conquered a large empire from the tiaga just south of the Umbrawood in the north, the Great Ocean in the East, the Deruptus Pass in the South, and the foothills of Tempus Mor to the west.
In Kael's D&D campaign, the Calabim capital of Prespur of the Storms was the largest city in the plane (I'm not sure this plane was Erebus). It was by the coast, very close to the Maelstrom (hence the name).
The Desert of Myrh itself is of course Malakim territory.
Both elven nations live and fight in the Umbrawood, and possibly lesser forests as well.
The Lanun's empire is made of waters rather than lands, although they do control numerous ports both on major continents and islands. Ship captains are considered higher ranking than the governors of the ports. Many Lanun follow the Overlords. Hannah follows them fanatically, while Falamar is not a religious man and is a bit uneasy around their followers.
The Orks live in the Jungles of Labuscum, especially around the Eternal Flame at the heart of Braduk the Burning. This is the crater through formed by the fall of Bhall through the center of old Bannor Capital, dragging the palace and her greatest temples into hell with her. When the Bannor found their way out they came though this flame, face to face with the mosters that their relatives had become due to Bhall's fall. The Bannor fled from the orks, and set up their empire just ourside this jungle. They have been constantly at war with the Clan of Embers, generally gaining more territory than they lost but not regaining their old capital, except during a truce negotiated by Rantine. They broke this truce (I'd guess that Orthus's barbarians attacked the Bannor first, and the Bannor retaiated against all orks), which really hurt Rantine's position in society.