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Sanmenxia, 
China
272,970 people lived in Sanmenxia in 2025. It is the 2130th largest of the world's 12,138 cities, and the 390th largest in China.
This is the UN's built-up area, drawn from satellite pictures and census maps rather than from the city limits, and the two can be a long way apart. The rule behind it.
Verified 2026-09-30 · 73 canaries
People · every five years · 1975 to 2050
How Sanmenxia grew
For every 10 people in Sanmenxia in 1975, there were 35.7 in 2025.
On the UN's projection it will have 252,233 people in 2050. It passed 250,000 people between 1995 and 2000.
projected (after 2025) · how sure the UN is: high moderate low
How to read this: each column is one of the UN's five-yearly estimates, 1975 through 2050, and taller means more people. Where a column is hatched the year has not happened yet. The strip under the columns is the UN's own confidence in each figure, palest where it is least sure; where it is blank the city was not on the list at all.
People · your family's years · 1975 to 2050
Sanmenxia through your family’s years
Put in the years your family were born. You’ll see how many people lived in Sanmenxia in each of those years, and when each of them turned 30.
China · every city · 2025
Where it is
How to read this: Sanmenxia is the dot in colour with a ring around it. The grey dots are the other cities of China in 2025, 2,082 in all, led by Shanghai, each drawn with an area that matches its people. Countries next door are outlines only.
Area and built-up land · km²
How much land it covers
In 2025, Sanmenxia covered 38 km², and buildings, roads and other built-up land covered 10 km² of it. That is 37 m² of built-up land for each person, about a square 6 by 6 metres. Since 1975, its built-up land has grown to 2.6 times its size, and its people are 3.6 times as many.
How to read this: the outer pale square stands for all the land the city covers, and the solid square inside it for the part with buildings, roads and the like on it. All three squares share a scale, so you can compare them by eye. A hatched one is a year the UN has projected.
Of every 100 people in China
Its share of China
Fewer than 1 in every 1,000 people in China lived in Sanmenxia in 2025 — about 1 in 5,263.
Ranked by people · 2025
Cities of a similar size
In the world, 2025
- 2122 Nacala Mozambique273,732
- 2123 Yibin273,660
- 2124 Asaka Uzbekistan273,582
- 2128 Saskatoon Canada273,454
- 2130 Sanmenxia272,970
- 2132 Cabanatuan Philippines272,890
- 2133 Nzérékoré Guinea272,866
- 2134 Dalla India272,778
- 2138 Guna India271,913
In China, 2025
- 2062 Suizhou282,058
- 2108 Pinggu274,753
- 2117 Xianning274,146
- 2123 Yibin273,660
- 2130 Sanmenxia272,970
- 2162 Wuqing269,223
- 2187 Yaguang266,899
- 2200 Jining265,293
- 2248 Jianhu259,681
How to read this: the number before each name is its place among all 12,138 cities in the world in 2025; bars are people, on one scale per list. Only cities that reach 300,000 people have a page here, so a gap in the numbers is a smaller city.
Apparatus
Sources and method
The figures for Sanmenxia are the UN's own, at five-year steps: an estimate for each of 1975 to 2025, then projection to 2050. Projected years are drawn hatched, and the UN publishes no range of uncertainty for a city. What a city means here, how the UN measures one, and why that number can differ from the one Sanmenxia publishes about itself: how the figures here are put together.
Sources: UN WUP 2025 · Natural Earth · flag-icons. Every source, its licence and how to cite it →
Verified 2026-09-30 · 73 canaries