The question of “how long is the Great Wall of China” is not as simple as it seems. While often perceived as a single, continuous structure built at one time, the Great Wall’s history is a complex tapestry of individual fortifications erected over centuries by various Chinese states. Understanding its length requires delving into its origins and the piecemeal construction that characterized its early phases.
Before the famed unification under the Qin Dynasty, various states within ancient China were already building defensive walls. These were not connected, monolithic structures, but rather independent systems designed to protect individual territories from rival states and nomadic incursions. As early as the 7th century BCE, the state of Chu initiated construction on what was known as the “Square Wall.” This marked one of the earliest known efforts to create a permanent defensive system in China, located within the northern reaches of Chu’s capital province.
Following Chu’s lead, other states began to establish their own fortifications from the 6th to the 4th centuries BCE. The state of Qi, situated in the south, developed an extensive perimeter wall. This Qi wall ingeniously incorporated existing river dikes, newly built bulwarks, and naturally impassable mountainous areas to create a formidable barrier that stretched to the Yellow Sea. Further inland, the Zhongshan state built a wall system strategically designed to deter invasions from the Zhao and Qin states to its southwest. The Wei state implemented a dual-layered defense strategy with its Hexi and Henan walls. The Hexi Wall, constructed during the reign of King Hui (370–335 BCE), served as a bulwark against the Qin state and nomadic groups from the west. It originated from the dikes along the Luo River and extended to Guyang, now within Inner Mongolia. The Henan Wall was focused on protecting Daliang, the Wei capital, and underwent repairs and extensions under King Hui. Even the Zheng state had its own wall system, which was later rebuilt by the Han state after conquering Zheng. The Zhao state notably completed both a southern and a northern wall, with the southern wall primarily aimed at defense against Wei.
The state of Yan also developed two distinct defensive lines: the Northern Wall and the Yishui Wall. These were crucial for defending against northern groups like the Donghu, Linhu, and Loufan, as well as the Qi state to the south. The Yishui Wall utilized the Yi River dike to create a defense against Qi and Zhao. In 290 BCE, the Yan state constructed the Northern Wall along the Yan Mountains, stretching from the Zhangjiakou area in Hebei, across the Liao River, to Xiangping (modern Liaoyang). This Northern Wall of Yan was the last major segment of the Great Wall constructed during the Zhanguo period, also known as the Warring States period.
The landscape of wall construction changed dramatically in 221 BCE when Shihuangdi, the first Qin Emperor, unified China by conquering Qi. Recognizing that the existing state walls hindered internal movement and administration, Shihuangdi ordered their removal. However, facing persistent threats from the nomadic Xiongnu in the north, he tasked General Meng Tian with a monumental project: to garrison the northern border and connect the remaining wall segments from Qin, Yan, and Zhao. This initiative, commencing around 214 BCE and lasting for a decade, aimed to create the “10,000-Li Long Wall.” Using the li unit of measurement, where 2 li is approximately 0.6 mile (1 kilometer), the name itself suggests a vast length. Hundreds of thousands of soldiers and conscripted laborers were involved in this massive undertaking. Despite this significant effort, with the fall of the Qin dynasty after Shihuangdi’s death, the wall was largely abandoned and fell into disrepair, highlighting the ongoing and evolving nature of the Great Wall throughout Chinese history. Therefore, when considering “how long is the Great Wall of China,” it is essential to remember its origins in these disparate, earlier walls and the subsequent, often discontinuous, construction phases across dynasties.
