The geography of Ancient China is often described by geologists in a system of three steps:
The first step is to the far west near present day Tibet. With the highest mountains on earth around here the climate is quite cold and in the summer quite warm this place is widely considered inhospitable, from -40℃ (-40 F) in the winter to 37℃ (100 F) in the summer. Due to this there aren’t many villages and when found villages are quite small.
The next step is the middle of China. It is covered with desert and a small amount of grassland. People here raise grazing cattle & yaks. There are some low hills but no snow. With cold winters and hot summers, this area was never densely populated.
The final step is the East. This area is accounts for around 95% of modern and Ancient Chinese population. Two long rivers flow through here, the Yellow and the Yangtze River. Here there is plenty of water for crops and agriculture flourished. In the North, wheat was the main crop and in the South, rice was more frequent.