"Conan stood over [the assassin], listening with tense expectancy. Up the street, around the next corner, he caught the shuffle of sandaled feet, the muffled clink of steel. These sinister sounds told him the nighted streets of Anshan were a death-trap." -- Robert E.Howard and L. Sprague de Camp: "The Flame Knife"
A nation south of the Vilayet Sea and the Ilbars Mountains, west of Venjipur and Vendhya.
It was the chief rival of Turan. Its capital was Anshan. It traded with Vendhya and with the Black Kingdoms, and probably with the Hyborian realms as well. Oil pools were to be found in its central regions.
Iranistan was a warm land, with moderate rains, especially on the seacoast. The land itself, however, was stony and infertile, and most Iranistani supplemented their diet with hunting and fishing from the extensive wilderness.
The Ilbars Mountains were arid with few trails, many box-canyons and twisting gorges. In the northern portions of the Ilbars, these mountains contained occasional small plateaus where Ilbarsi tribesmen eked out a hunter-gatherer existence. In Drujistan, the lands were more precipitous, and there were few places to settle. Drujistan was believed to be a "land of demons" and feared by the Iranistani peoples.
There was no "state religion" in Iranistan; the temple district of Anshan was a confusing maze of tiny hut-shrines beside huge stone temples. The strength of a given cult was directly tied to the associated tribe's favor with the king.
References: Bloodstained God, Road of Eagles, Flame Knife, Shadows in the Skull, Conan of the Isles, Conan and the Manhunters, Conan the Hero, Conan and the Shaman's Curse.