"...a tall and massive wall, which enclosed the palaces of the ruling caste, descendants of those Stygians who centuries ago had come southward to hack out a black empire, and to mix their proud blood with the blood of their dusky subjects." -- Robert E. Howard: "The Snout in the Dark"
Northernmost of the Black Kingdoms situated south of Stygia. There were Kushite villages along the shore of the Western Ocean, then a band of thick forest. Inland stretched a savanna, which ended in eastern hills. Beyond this was the Southern Desert, only nominally part of the kingdom.
Its capital city was called Shumballa (also known as Meroê), the largest in the Black Kingdoms. It was based on pre-Stygian ruins, and its ancient stone walls were frequently patched with log palisades where the walls had collapsed.
Kush gave its name to the whole southern part of the world-continent. Barachan pirates were the first northerners to raid and trade with Kush. Later, Argos and Zingara had a thriving traffic in gold, ivory silver, copra, pearls, and slaves. Kush imported beads, silks, sugar, and brass-hilted swords.
The kingdom was ruled by a brown-skinned, part-Stygian race which despised the black lower classes.
References: Hyborian Age I, Letter to p. Schuyler Miller from R.E.H., Queen of the Black Coast, Castle of Terror, Snout in the Dark, Drums of Tombalku.