When we think of Henan, we think of the Central Plains. Yes, what we usually call the Central Plains actually refers specifically to Henan, so Henan has a name: the Central Plains Province. And do you know where the provinces with the most Chinese mouths are? That's right, It's Henan Province, with a population of over 100 million, more than the population of many countries in the world!
And because it is located in the Central Plains, it has become a "place where soldiers and families must fight" for generations. If you don't believe it, you can look at the map, Henan's geographical location is just in the middle of China, the mountains and rivers in the east and west are dangerous, plus the Kyushu Thoroughfare; on the other hand, the ancient division was mainly bounded by Hangu Pass, the Yellow River or Jianghuai, so that the place did not cause competition between various forces, which was obviously impossible. Therefore, there are many ancient battlefields in Henan, such as Guandu, Xingyang and Nanyang. Henan, with its large population, has unfortunately become a source of soldiers. This leads to a reduction in labour and a compromise in the ability to withstand natural disasters and sustain agricultural production, leading to disasters.

For example, the great drought in Henan in 1942, according to the "Chronicle of Henan Province and Population":
In 1940, the population of Henan province was 30.67 million; by 1942, only 27.98 million people remained; in 1943, 25.95 million people remained; by 1944, the population had dropped to 24.71 million.
It can be seen that in just four years, the population of Henan Province has decreased by 5.96 million, and in addition to the normal population increase and decrease and the impact of war, it is estimated that the number of people who starved to death in 1942 should be more than 3 million. Of course, the great famine of 1942, in addition to the impact of the drought, was more of a man-made disaster, that is, war and man-made sins.
But today we are not telling the story of the drought in Henan, but about the migration of Henan people. If it is a Henan people know, in history, once there was a disaster in Henan, basically they would flee west, that is, through Tongguan, along the Longhai line to Shaanxi, rather than other places, such as Shandong, Hebei, Hubei, there are, but almost very few. So the question is, why is that?
We all know that Chinese migration, that is, leaving home, generally can not escape this "direction": to rely on relatives and friends.
If there is a famine and you have an old farmer who has never been out of the local area in your life, where can you go to escape the famine, then there are three natural options:
Heard where there is food and where to go;
Where to go with relatives;
Where to go near.
Obviously, due to geographical location, Henan Province is surrounded by large population provinces, Shandong, Hebei, Hubei, which province is not a large population, although there is some gap with Henan, but it is still ranked relatively high in the country's provinces, such as Shandong is second only to Henan' population province. Therefore, whenever there is a major drought, Henan people can only go to Shaanxi, where the population is relatively small, and then move from Shaanxi to Gansu and Xinjiang, which are even less populous.
Henan's location in the country as well as in the surrounding provinces
After all, as a neighbor of Henan, Shaanxi's Guanzhong and western Henan have more contacts, and the dialect is relatively close, so there is a second one who first turns to relatives, and there is a second time when they flee the famine, and later they run to the hometown that went first, like a snowball, gradually forming a wave of immigration.
Another reason is that after the rebellion during the Tongzhi period of the Qing Dynasty, Shaanxi had ten rooms and nine empty spaces, and the population became smaller, plus Guanzhong has been a high-yield area since ancient times, which can not only support itself, but also support others. However, Henan has a large population density, many disasters and famines, many Yellow River breaches, many disasters, and Shaanxi has food, so naturally it is to flee to Shaanxi.
Of course, there are also more Henan immigrants to Jiangsu and Zhejiang, Shanghai, Hangzhou, Nanjing and other places, and many people in the south are also Henan immigrants for more than a thousand years. But in general, Henan's ability to resist disasters is not as good as Shandong's, and whenever there is a major disaster, it is always a heavy casualty and desperate.