The ancient and rich Weihe Plain has nurtured many human civilizations. in this

Weihe Plain, also known as Guanzhong Plain or Weihe Basin, is a graben structural plain. It is located between Qinling Mountain and Weibei Mountain (Laolongshan Mountain, Eluan Mountain, Wangyaoshan Mountain, Yaoshan Mountain, Huanglong Mountain, etc.). ). It starts from Baoji in the west and reaches Tongguan in the east, with an altitude of about 323-800 meters, a length of about 350 kilometers from east to west and an area of about 36,000 square kilometers. Because it is between Hangu Pass (later also called Tongguan Pass) and Dasanguan Pass (once said to be between Hangu Pass, Dasanguan Pass, Wuguan Pass and Xiaoguan Pass), it was called "Guanzhong" in ancient times and also called "Qinzhong". The Spring and Autumn Period and the Warring States Period were the hometown of Qin, including Xi 'an, Baoji, Xianyang, Weinan, Tongchuan and Yangling demonstration areas. It is about 350 kilometers long from east to west, with an average elevation of about 500 meters. Narrow in the west and wide in the east, it is known as "Qinchuan in 800 Li".

Weihe Plain is a graben, which is formed by the alluvial of Weihe River and its tributaries Jinghe River and Luohe River, and belongs to the key main part of Weihe fault basin belt. Irrigation has been developed since ancient times and is rich in wheat and cotton. It is an important commodity grain producing area in China. It was the first time that China was called "a golden city with thousands of miles, a land of abundance".

There are natural terrain barriers on all sides, which are easy to defend but difficult to attack. Since the Warring States period, there has been a saying of "one country, four blockades". Therefore, in the Han Dynasty, Zhang Liang summed up the advantages of Guanzhong with "a golden city of thousands of miles" and persuaded Liu Bang to make it the capital of Guanzhong. During the Warring States Period, Zhang Yi told Qin Chen about the plan of "Lian Heng", praising Guanzhong's "fertile land, rich people, numerous chariots, tackling all kinds of difficulties, fertile fields and thousands of miles, and accumulating abundance", saying that "this so-called rich land is also a country under the world", more than half a century earlier than Chengdu Plain was awarded the title of "Land of Abundance". This is because Guanzhong has become a treasure trove of geomantic omen and the capital of emperors since Zheng Guoqu was restored in the Warring States Period.