Manchuria is now most often associated with the three Chinese provinces of Heilongjiang, Jilin, and Liaoning. The former Japanese puppet state of Manchukuo further included the prefectures of Chengde (now in Hebei) and Hulunbuir, Hinggan, Tongliao, and Chifeng (now in Inner Mongolia). The region of the Qing Empire referenced as Manchuria originally further included Ussuri and Primoskiy Krais and the southern part of Harbin Oblast.

Manchuria consists mainly of the northern side of the funnel-shaped North China Craton, a large area of tilled and overlaid Precambrian rocks spanning 100 million hectares. The North China Craton was an independent continent before the Triassic period and is known to have been the northernmost piece of land in the world during the Carboniferous. The Khingan Mountains in the west are a Jurassic mountain range formed by the collision of the North China Craton with the Siberian Craton, which marked the final stage of the formation of the supercontinent Pangaea.

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