The great wall was built in the northern area of the emperor because that was where all the mongols where coming from the purpose of the Great Wall of China was to keep all the outsiders from getting inside the emperors kingdom. Qin didn't want small walls covering each village he just wanted a big wall that protected everyone inside including himself. Qin also decided to build the wall there so all the people living in the south side will be separated from all the mongols from the north. But the main reason was to protect his kingdom and also he didn't want to die from the savages from outside the great wall.
The walls, together with beacon towers created an elaborate defensive system providing Chinese society with a safe and peaceful environment. During the spring and Autumn Period and Warring States Period, there were many states, so they built separate sections to prevent invasion by other states. Furthermore, states in the northern part of China built some sections to defend against the northern nomadic tribes. In the Qin Dynasty, the Wall was mainly used to protect the country from nomadic tribes. In the reign of Emperor Wu of Western Han, the Wall played a significant role in protecting the main force as well as being a military base in the wars. Every time the country conquered new lands, the Wall would be extended, so that the local military force would be strengthened. With the help of the Great Wall, the Han Dynasty conquered more and more regions in north-western China.
The walls, together with beacon towers created an elaborate defensive system providing Chinese society with a safe and peaceful environment. During the spring and Autumn Period and Warring States Period, there were many states, so they built separate sections to prevent invasion by other states. Furthermore, states in the northern part of China built some sections to defend against the northern nomadic tribes. In the Qin Dynasty, the Wall was mainly used to protect the country from nomadic tribes. In the reign of Emperor Wu of Western Han, the Wall played a significant role in protecting the main force as well as being a military base in the wars. Every time the country conquered new lands, the Wall would be extended, so that the local military force would be strengthened. With the help of the Great Wall, the Han Dynasty conquered more and more regions in north-western China.