During the Qing Dynasty, although there was a difference between Outer Mongolia and Mongolia, they were both important parts of China, and they belonged to the border areas of China, and the Mongolian region also built a number of cities in history, but these cities have not been continued due to factors such as war.
During the Qing Dynasty, not only did the Great Wall not build on the Mongolian border as it did during the Ming Dynasty, but even the walls of the city were not built.
The Qing Dynasty was an important stage in the development of cities in Mongolia, and the cities in modern Mongolia were basically the pattern formed during the Qing Dynasty. So during the Qing Dynasty, why not build walls in these cities in Mongolia?

The role of the city walls
Many people believe that the city wall is the most effective defense system in the era of cold weapons, and in the period of hot weapons, this military defense system is difficult to play a role, and the reason why the Ming Dynasty built tall walls is because of the emergence of hot weapons with huge lethality such as Hongyi cannons in that period.
In fact, this argument is difficult to stand, we look at the Second World War, the hot weapon war that occurred in China, the city wall is still an important pass, is still a key point of contention.
For example, the famous Barev Line, on the east bank of the Suez Canal, is still built 170 kilometers long and 7 kilometers deep, with a strong dense network of machine guns, artillery, tanks, etc.
The Barev Line remained a fortification of the city walls, and it was clear that as long as the war took place on land, a defensive system like the wall would still have military value.
There are also people who believe that the Qing Dynasty did not build the Great Wall on the frontier, and that the city wall stemmed from military self-confidence, such as Kangxi's "The Great Wall Built by Mengtian": "Wanli ran to haiya, and one after another dispatched exaggerations." At that time, the strength of the people was exhausted, and the world belonged to the Er family."
It is believed that the Qing Dynasty can rely on military strength to impose military suppression on the frontier. These are not considered from a specific environmental and social perspective, but are considered purely from a military point of view.
So why didn't the Mongol region build walls? This starts with the formation of cities in Mongolia.
The rise of cities in mongolia
In the Liaojin Dynasty, some prefectures and counties were established in the southern part of the desert, and after the establishment of the Mongol Empire, the urban civilization of the Central Plains gradually penetrated into the Mongolian region, and some magnificent cities were also established on the Mongolian steppe, such as the Mongolian capitals of Harz and Lin, Yuan Shangdu, Yuan Dadu, etc., which are the symbols of the Mongolian material civilization and spiritual civilization.
However, in the last year of the Yuan Dynasty, these cities were destroyed one after another, and Yuan Shangdu, ArunMuji, etc. were buried in a ruin.
From the Ming Dynasty to the Qing Dynasty, there were almost no cities in the full sense of the word in the Mongolian region.
Most of the altitude in Inner Mongolia is above 1000 meters, the east is the Daxing'an Mountains, the central and western parts are daqingshan and Helan Mountains, Ula Mountains and other vast grasslands, there are Hulun Lake, Bell Lake, etc. Although there are so many lakes, most of them are composed of barren gravel.
Inner Mongolia has a temperate continental monsoon climate, with temperatures as low as minus 40 °C in winter and very long winters, with average annual temperatures of 1-10 °C. Obviously, this climatic condition is not suitable for crop growth.
People's life is inseparable from water, crop growth is also inseparable from water, and most areas of Mongolia are arid hills, the average annual precipitation is 50-400 mm, this area is obviously not suitable for life, as well as agricultural production.
The economy is the basic driving force for the development of a city, and in feudal society, agriculture is the basic economic pillar. Agricultural development is an important condition for urban development. The nomadic life has no fixed place to live, so it is impossible to form settlements, let alone cities.
The Mongolian region is mainly nomadic, and people migrate with aquatic grass and livestock, and there is no city-state. For a long time, handicraft industry did not develop, resulting in relatively backward commerce, and commerce in Mongolia was mostly barter.
This mode of production seriously restricted the rise and development of the city, people are the main body of the city, due to the limitations of the geographical environment, the population of the Mongolian region in the Qing Dynasty is not large and very scattered. Moreover, the nomadic production mode determined that the way of life of most Mongols was dominated by scattered yurts, and this decentralized way of living continued until the Republic of China and even the new China period.
Mongolia is a relationship with the flag league, and unlike the inland state capitals, the inland state capitals will form cities of varying sizes, which are not only economic centers, but also centers of political management. The formation of cities is closely related to political power, and the flag league seats in Mongolia rarely form cities.
After the establishment of the Qing Dynasty, it took more than 100 years to establish a political model with the Flag League as the core in the Mengdu region, which is an administrative organization and a military organization, and the alliance will set up a league leader and a deputy league leader.
Candidates are selected and nominated by the Riksang in the various Zazaks and their idle princes of the League, and submit their requests. The League is not a first-level administrative body above the Zasak, so there is no League Affairs Gate and corresponding officials, nor is it allowed to interfere casually in the internal affairs of the Zasak Banner.
Although some administrative bodies will be formed, and these institutions will gradually form settlements, but they generally occupy a small area and have a relatively small population. Therefore, it was impossible to support the development of handicrafts and commerce.
The essence of the city lies in the gathering, and the Qimengzhi office lacks the gathering power and radiation power, so it cannot form a city, and the political center formed in mongolia is mainly from the power of the central dynasty, not the locality.
After the Qing Dynasty incorporated Mongolia into the Chinese territory, a large number of Han Chinese continued to pour into Mongolia, and the Mongolian region entered a stage of development between nomadism and farming, which changed the economic form, production methods and living habits of Mongolian society.
The rise of Mongolian cities
For a long time, the Outer Mongolia region was in a state of dispersion and centrifugal force, and after the unification of the Qing Dynasty, Outer Mongolia was constantly affected and threatened by the separatist forces of the Dzungars. In the twenty-seventh year of the Kangxi Dynasty (1688), Kaldan, instigated by Tsarist Russia, attacked the Uju Muqin region of Inner Mongolia and threatened Beijing. In order to ensure the stability of the frontier, Kangxi marched three times, and in present-day Keshketengnan, Inner Mongolia, defeated Kaldan and forced him to retreat to northern Mobei.
However, the threat of the Dzungars has not been completely resolved, and has always been a problem for the heart, so the Qing Dynasty was forced to invest a large amount of military force and strategic materials to solve the Mongol problem. Under the influence of the national security strategy, the Mongolian region, especially the cities of Outer Mongolia, have sprung up one after another.
Later, the Qing court set up important institutions such as ministers and generals in mongolia, and successively promoted the formation of important cities such as Kulun, Uriasutai and Kolendo.
The rise of cities in Outer Mongolia was directly related to the implementation of the Qing Dynasty's national security strategy. Although these cities had a single function and a small scale in the early stage of their rise, in the subsequent development process, a considerable number of cities were able to continuously superimpose new functions to promote the renewal and development of cities; some cities with military functions failed to achieve transformation, and declined due to the transfer of the National Security Strategy of the Qing Dynasty.
Outer Mongolia and Inner Mongolia are not only relatively different in physical geography, but also Inner Mongolia is more closely related to the agricultural civilization in the interior, because during the Qing Dynasty, many settlements were formed, such as Fengzhen and Naturalization.
Due to the decline in the military strategic position of the southern region, during the Qing Dynasty, few military towns were established in inner Mongolia. Due to the relatively convenient transportation between Inner Mongolia and the interior, the situation of immigration from the interior to Mongolia is also relatively frequent.
These immigrants brought the more advanced farming culture from the interior to Mongolia, changed the economic structure and demographic structure of Inner Mongolia, and thus provided preparations for mongolian urban development.
The size of a Mongol city in the Qing Dynasty
City size is an important indicator to measure the development of a city, during the 200-year reign of the Qing Dynasty, although the cities in Mongolia have developed greatly, but compared with the inland regional cities, both in size and population, they are far behind.
Moreover, during the Qing Dynasty, these cities had a strong political and military purpose, and the population of the cities was generally relatively small, and the proportion of military personnel was relatively high.
For example, in the largest city at that time, Kulun, there were about 30,000 people, most of whom were lama monks, more than 5,000 merchants, and more than 2,000 officers and soldiers stationed.
With the exception of a few important political and military towns in Mongolia, most cities have cities but no walls, especially those that are spontaneously formed by trading, and the entrances to these streets are usually two gates, or simply two wooden pillars, some of which are covered or some are empty.
Most of these cities are centered on temples, so commercial streets can only be built separately. At the same time, Mongolia believes in Lamaism, and Lamaism is not accustomed to building houses on the street, but is independent of districts.
The rise and development of cities in mongolia in the Qing Dynasty is closely related to the security strategy and ethnic policy of the Qing Dynasty, and also has strong regional characteristics and religious overtones, and temples are the main components of urban public buildings. At the same time, due to religious reasons, relatively independent buying and selling cities have been formed, as well as multi-core cities.
Therefore, it is not that the Qing Dynasty was unwilling to set up the Great Wall or city wall on the frontier, but because of the unique natural environment and urban form of the Mongolian region, it was impossible to form a city with a large population like the Central Plains. Moreover, the formation of these cities is mostly for political, religious and other reasons, and it is impossible to live in a large scale and build a wall to encircle. And these cities, once they lose their political and military role, will soon decline. Combining the above factors, it was the main reason why the Qing Dynasty did not build walls in Mongolia.