From the White Wolf Wiki, the most complete White Wolf reference

If the Tempest is a "sea" in the Underworld, the Dark Kingdoms are islands in that sea. Each Dark Kingdom is "the afterlife" for the dead of a particular culture. Those wraiths who die within the confines of a particlar region are sent to the appropriate Dark Kingdom.

The major Dark Kingdoms are:

• The Dark Kingdom of Clay, Karta. Home to the Aboriginies of Australia.
• The Dark Kingdom of Iron, Stygia. Stygia began as the underworld for Medeterranian countries, but over the centuries has grown to claim most of the Western world.
• The Dark Kingdom of Ivory, the Bush of Ghosts which claims authority over the dead of Africa.
• The Dark Kingdom of Jade, the Yellow Springs. Home to Asian dead.
• The Dark Kingdom of Obsidian, the Flayed Lands and the original Dark Kingdoms of the Americas.
• The Dark Kingdom of Sand, Amenti. Home of the Gods and Undying of Ancient Egypt.

There are other realms which, while they are still Dark Kingdoms, do not have a "Dark Kingdom" title.

• The Sea Which Knows No Sun, the Polynesian afterlife.
• Swar, the City of Delights and the domain wherein the Indian Dead while away their existence.
• The Mirrorlands, the end of the road for Les Invisibles from the Carribean.

And we would be remiss to leave out:

• The Dark Kingdom of Wire, including Auschwitz and other sites, are the largest populations of restless dead, thanks to the crimes of Nazi Germany. Not a true Dark Kingdom; just a collection of Necropoli.