How Long Is the Great Wall of China?

The official answer: 21,196.18 kilometres

The Great Wall of China is 21,196.18 kilometres (13,170.70 miles) long. That is the official figure announced in June 2012 by China's National Cultural Heritage Administration, at the close of a six-year national survey — the first and so far only full-scale field measurement of every known Great Wall remain, conducted section by section on the ground rather than estimated from maps.

The number covers everything the survey teams could verify: walls, trenches, towers, passes, and fortifications built by every wall-building dynasty, spread across 15 provinces and regions of northern China. In total the survey catalogued 43,809 individual heritage records, of which 42,073 carry verified coordinates — the dataset this archive maps.

To put 21,196.18 km in perspective: the equator measures about 40,075 km, so the surveyed Great Wall is longer than half the distance around the Earth. It is roughly the distance from New York to Sydney and halfway back. No other structure built by hand comes close.

One caution before the details: the Great Wall is not a single continuous wall. It is a network of separate defensive systems, built, extended, and abandoned by different dynasties over more than two thousand years, often running in parallel lines hundreds of kilometres apart. That is precisely why “how long is it?” has more than one honest answer.

Why you see three different numbers

Look up the Wall's length in different references and you will meet at least three figures. All of them are “correct” — they just answer different questions.

About 5,000 km is what the Wall's Chinese name promises. 万里长城 — wànlǐ chángchéng, “the ten-thousand-li long wall” — converts to roughly 5,000 km at the modern value of the li. The name is poetic scale, coined long before anyone could measure the Wall, and it stuck.

Figures in the 6,000–6,700 km range dominated reference books for most of the 20th century. They were estimates of the Ming dynasty main line from Shanhaiguan on the coast to Jiayuguan in the Gobi, made from maps and partial surveys before modern fieldwork was possible.

8,851.8 km is the measured length of the Ming Great Wall specifically — the brick-and-stone wall of the postcards — announced in April 2009 as the survey's first completed phase, covering ten provinces. This site rounds it to 8,850 km in passing mentions.

21,196.18 km is the full answer: every dynasty, every branch line, every trench and natural barrier the survey could verify, announced in 2012 when the remaining provinces were done.

A reliable rule of thumb when sources disagree: a figure between 6,000 and 8,900 km means the Ming wall; 21,196 km means all walls of all dynasties. The two numbers differ because most of the Great Wall is not the Ming wall — it is the older, mostly rammed-earth systems of the Han, the Warring States, the Jin, and half a dozen other eras.

What counts as “wall” in that number

The survey's total is not 21,196 km of brick battlements. Chinese wall-builders were pragmatic: where a mountain ridge or a river already blocked cavalry, they simply enrolled it in the defensive line rather than building on top of it. The official length therefore counts three kinds of barrier: artificial wall, excavated trenches and moats, and natural barriers — cliffs, ridges, and rivers formally incorporated into the system.

The Ming figure shows the proportions precisely. Of its 8,851.8 km, the 2009 survey measured 6,259.6 km of actual constructed wall, 359.7 km of trenches, and 2,232.5 km of natural barriers. Roughly one kilometre in four of the “Ming Great Wall” is a mountain or a river doing the wall's job.

The same taxonomy runs through the survey's 43,809 records and through this archive: wall segments, trench and moat lines (the jièháo border trenches of the Jin dynasty form most of them), and the towers, passes, and forts that armed the line. Our architecture pages define each type, and the interactive map renders artificial wall, trench, and natural-barrier segments in distinct styles so you can see the mix for yourself.

Length by dynasty, from the survey data

Official per-dynasty totals beyond the Ming figure were never published as a single table, but this archive's dataset allows an honest approximation: summing the measured length of every located wall record by dynasty. The sums below cover the 42,073 located records (of 43,809 surveyed) and count constructed segments only — so they run below the official totals, which also include natural barriers and records the survey could not locate. Read them as relative scale, not gospel.

How long would it take to walk?

Walking the full 21,196 km would take roughly 18–20 months — about 540–600 days — of continuous hiking. In practice nobody has done it, and nobody can: the Wall is thousands of disconnected segments, many in desert, on private land, or protected from foot traffic.

The classic real-world benchmark covers the Ming wall only. In 1907–08 the American explorer William Edgar Geil trekked east to west from Shanhaiguan to Jiayuguan — the journey behind the world's first Great Wall monograph. Modern long-distance hikers follow his example in spirit, covering a single section over two to four weeks.

Is the Wall getting shorter?

The official length is a heritage inventory, not a count of standing masonry — it includes segments the survey graded as badly eroded or vanished entirely, where fieldwork confirmed the line but little or nothing survives above ground. Across most of the surveyed length, especially the older rammed-earth systems, what remains is a low remnant rather than the restored battlements of the postcards.

Erosion, sandstorms, farming, and construction have been wearing the remnant down for centuries, and surveys and press reports over the past two decades have documented substantial ongoing loss. The map encodes the survey's preservation grades directly: solid lines for well-preserved wall, dashed and dotted lines where it is fading or gone. Zoom into almost any western province and the dotted lines dominate — the most honest picture of the Wall's condition you can get.

Quick answers

Sources

• China National Cultural Heritage Administration, national Great Wall survey (2012) — see our sources & methodology
• SACH / State Bureau of Surveying and Mapping, Ming Great Wall survey announcement (2009)
• William Edgar Geil, The Great Wall of China (1909)