[quote=Dinh AaronMk]
Given that's the steppe region without much in the way for farming or long-term settlement the population would most likely be lower than normal. Though you're a bit on the big side ~1m would have been an average. Though also given the area I doubt there'd be much going on to support a static population a quarter or half that. Most of anything else would be nomadic bands just moving through with their goats or horses or what not.So a few hundred thousand maybe spread between a few permanent settlements and the rest moving around would be my best guess.
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Those lakes would be fresh water since they are attached to a river system that feeds the ocean. That means that the area he has marked off won't look like the Gobi. It would be more like the area where the deep midwest meets the Great plains. More Iowa than Mongolia.