Seen as a border, the Great Wall of China is not one line but many: a chain of walls, trenches, towers and passes that successive Chinese states built along their northern frontier over more than 2,000 years, from the 7th century BC to the fall of the Ming dynasty in 1644. China’s 2012 national survey measured all surviving sections at 21,196 kilometres, in a long arc from Liaodong in the north-east to Lop Lake in the west. The best-known Ming wall accounts for 8,850 kilometres of that. The line matters because it roughly traces the edge of the Mongolian steppe. It was where farming China met the herding peoples to the north, and every dynasty drew it a little differently.
Because each state put the frontier where its own power ran out, the Great Wall is best understood as a sequence of borders laid over one another. The Chinese name reflects this. Changcheng, the “long wall”, first appears in the histories of Sima Qian, but most later dynasties avoided the term because of its links to the First Emperor. They preferred words such as sai, “frontier”, or bianqiang, “border wall”. Only under the Qing did “long wall” become the umbrella term for all of them.
Rammed Earth Between Rival States, 7th–3rd Centuries BC
Many of the first walls were built between Chinese states rather than against outsiders. During the Spring and Autumn period and the Warring States period that followed, the states of Qi, Chu, Qin, Wei, Zhao, Yan, Han, Zheng, Lu, Zhongshan and Zhou all fortified their borders. The walls were built to stop infantry armed with swords and spears. They were made of stone where it was available, or of earth and gravel pounded hard between wooden boards, a technique known as rammed earth. The walls along the northern edges of these states became the raw material for what came next.
Qin Shi Huang, Meng Tian and the Line of 221 BC
When Qin conquered the last of its rivals in 221 BC, its king, now the First Emperor, ordered the internal walls torn down so that the old states could not rise again. The northern walls were kept and joined up. He sent the general Meng Tian north with an army said to number 300,000, which drove the Xiongnu back about 1,000 li, roughly 400 kilometres. The defences Meng Tian started were said to run more than 10,000 li, from Lintao in the west to Liaodong in the east.
That number is where the later name Wanli Changcheng, the “ten-thousand-li wall”, comes from, although “ten thousand” in Chinese often just means countless. The Qin builders worked by the rule of “build and move on”, using local stone in the mountains and rammed earth on the plains. They were not fixing a permanent boundary. No record gives the exact course of the Qin wall, and very little of it survives.
The Han Push West to the Jade Gate
The Han dynasty, which ruled from 202 BC to AD 220, repaired the Qin line and then carried the frontier much further west, into the Hexi Corridor and the Gansu desert, to protect the road that became the Silk Road. Han fortifications begin at Yumen Pass, the Jade Gate, and Yang Pass south-west of Dunhuang, where the one road linking China with Central Asia passed through. The most remote Han border posts are at a place called Mamitu, “horses losing their way”, near Yumen. Walls like these also worked as customs lines, controlling who crossed and collecting duties on goods moving along the Silk Road.
Walls of the Northern Wei, Jin and Western Xia
After the Han, the line kept moving, and not only Han Chinese dynasties built it. The Northern dynasties and the Sui repaired and extended the walls at great cost. Dynasties founded by peoples from beyond the frontier built their own: the Xianbei-ruled Northern Wei, the Khitan Liao, the Jurchen Jin and the Tangut Western Xia. Their lines ran further north than any Han wall, reaching into what is now Mongolia. The Jin, who ruled northern China from 1115 to 1234, left about 4,010 kilometres of frontier works. The Tang and Song, by contrast, did almost no wall-building in the north. For these periods the border moved with the dynasty, and the ruins show where each one stood.
The Tumu Disaster of 1449 and the Ming Retreat to the Ordos
The Ming dynasty took power in 1368, and its early fortresses included Jiayu Pass, built around 1372 at the narrowest point of the Hexi Corridor. It became the western end of the Ming wall and the gate through which envoys and merchants from Central Asia entered China. The fort is a trapezoid with 11-metre walls and a perimeter of 733 metres, and it was strengthened when Timur was expected to invade China. He died on the march, and the attack never came. The great Ming building programme followed a military catastrophe. On 1 September 1449, at the fortress of Tumu, the Oirat Mongol leader Esen routed a Ming army and captured the Emperor Yingzong.
After Tumu, the Ming drew the line defensively. Mongol groups now held the Ordos Desert inside the great northern bend of the Yellow River, so the new wall ran along the desert’s southern edge instead of enclosing the bend, leaving it outside the wall. At Piantou Pass in Shanxi the wall splits in two. The Outer Great Wall follows the modern Inner Mongolia–Shanxi boundary into Hebei. The Inner Great Wall runs about 400 kilometres south-east through the Pingxing and Yanmen passes before rejoining it at Sihaiye, in Beijing’s Yanqing district. In the mid-15th century the Ming also built the Liaodong Wall, a simpler earth dike with moats on both sides, to protect the farmland of Liaodong from Mongol and Jurchen raids.
Qi Jiguang’s Brick Towers, 1567–1570
The Ming wall differs from earlier ones in its material. Brick and cut stone replaced rammed earth, bound with a mortar of sticky rice soup and slaked lime. Up to 25,000 watchtowers may have been built along it. Mongol raids kept coming, so the stretch guarding Beijing was the most heavily reinforced. Between 1567 and 1570, under the general Qi Jiguang, 1,200 watchtowers were built between Shanhai Pass and Changping, and older earthen sections were faced with brick. The sections around Beijing are the ones most visitors see today. At Jinshanling it climbs steep ridges for 11 kilometres, 5 to 8 metres high, with 67 watchtowers. The highest of them, Wangjing Lou, stands at 980 metres.
Wu Sangui Opens Shanhai Pass, 1644
The wall’s eastern anchor was Shanhai Pass, the “First Pass Under Heaven”. It controls the narrow coastal corridor between the Yan Mountains and the Bohai Sea, the only easy land route from Manchuria into the North China Plain, and the part of the wall that runs into the sea there is called the Old Dragon Head. After the Manchus took Liaodong, the pass still held. It fell not to an assault but to a deal. On 25 May 1644, with Beijing already taken by the rebel Li Zicheng, the Ming general Wu Sangui opened the gates to the Manchus, hoping to use them against the rebels. Instead the Manchus took Beijing for themselves, and their Qing dynasty, proclaimed in Shenyang in 1636, went on to rule all of China.
The Qing made the wall redundant as a border. Once Mongolia was absorbed into the empire, the frontier lay far to the north, and military work on the wall stopped. The dynasty still drew internal lines of its own. In the late 17th century it planted the Willow Palisade, a system of ditches and willow-lined embankments that roughly followed the old Liaodong Wall, to keep Han Chinese settlers out of the Manchu homeland.
Surveyors Measure the Line: 2009 and 2012
There has never been an agreed definition of what counts as part of the Great Wall, which made its length hard to pin down. Modern surveys tried to settle the question. In 2009, surveyors using infrared range-finders and GPS found about 180 kilometres of previously unknown Ming wall hidden by hills, trenches and rivers. In 2012 China’s National Cultural Heritage Administration published its full result. It counted 10,051 wall sections, 1,764 ramparts or trenches, 29,510 individual buildings and 2,211 fortifications or passes, spanning 21,196.18 kilometres. The Ming line alone came to 8,850 kilometres: 6,259 of built wall, 359 of trenches and 2,232 of natural barriers such as hills and rivers. About half of all surviving sites are in Inner Mongolia (31 per cent) and Hebei (19 per cent).
The same survey showed how much has already been lost. About 22 per cent of the Ming wall, 1,961 kilometres, has disappeared, taken as stone for houses and roads, destroyed for construction and mining, or worn away by sandstorms in Gansu. As recently as 2023, workers in Shanxi widened a gap in the wall to make a shortcut for an excavator. Why different sources give such different totals is explained in our piece on how long the Great Wall of China is. The western passes that the Han walled are the subject of our Silk Road guide, and Rome’s much shorter answer to the same frontier problem is described in our look at Hadrian’s Wall.