China is a nation of superlatives. It is one of the largest countries in the world by total area, spanning nearly 9.6 million square kilometers. This sheer size conjures an image of endless, open space, a vast landmass capable of absorbing its massive population with ease. Yet, this perception is a profound geographical illusion. While China is indeed vast, its population is not spread evenly across its territory. In reality, the country is one of the most geographically dense and, in a functional sense, “overpopulated” places on Earth, a fact best understood through a single, invisible line: the Heihe-Tengchong Line.The Great Divide: The Hu Line
In 1935, the geographer Hu Huanyong drew a diagonal line across China, running from the city of Heihe in the far northeast to Tengchong in the southwest. This line, now famously known as the Hu Line, divides China into two halves that are nearly equal in area, but wildly unequal in population.The statistics are staggering and reveal the true nature of China’s density:
West of the Line: This half comprises approximately 57% of China’s total landmass. It is dominated by high-altitude plateaus, deserts (like the Gobi and Taklamakan), and rugged mountains. This vast, empty territory is home to only about 6% of the country’s population.
East of the Line: This half, which accounts for roughly 43% of the land, is where the overwhelming majority of the population resides—around 94% of China’s 1.4 billion people.This means that the vast majority of the Chinese population is crammed into an area roughly the size of Western Europe, but with a population density that far exceeds most of the world’s most crowded nations.
The True Density of Habitable China
When we talk about China’s population density, the official figure of around 150 people per square kilometer (which is lower than countries like Germany or the UK) is misleading. That number is an average across the entire landmass, including the uninhabitable deserts, mountains, and frozen plateaus of the west.
The functional density—the density experienced by the average Chinese citizen—is far higher. The eastern half of the country, the true “habitable China,” has a population density that rivals or exceeds that of densely populated countries like Bangladesh or South Korea. This concentration is driven by geography: the east is home to the great river basins (the Yangtze and Yellow Rivers), fertile plains, and a climate suitable for intensive agriculture and large-scale urbanization.
The consequence of this extreme concentration is the daily reality of what is often termed “overpopulation.” It manifests in the scale of China’s megacities, where urban populations can exceed 20 million; in the sheer volume of its transportation networks; and in the intense competition for resources, education, and opportunity.
A World of Difference
The perception of China as a vast, empty land is a Western-centric view that fails to account for the constraints of its geography. While the country is large, the portion of it that is truly livable is relatively small. This geographical reality is the key to understanding the intensity of Chinese society, the scale of its infrastructure projects, and the historical necessity of its policies.
The next time you consider China’s size, remember the Hu Line. It is a powerful reminder that size is not the same as space, and that the world’s most populous nation is, for all its vastness, fundamentally a story of extreme geographical concentration. It is this density, not just the total number of people, that defines the Chinese experience and makes it feel so intensely crowded compared to the rest of the world.
