In Population Distribution you saw where people live. One of the biggest changes of the last two centuries is where within a country they live: more and more of them in cities. World Geography's largest cities topic shows the giants.
Key idea
Urbanization is the growth in the share of a population living in urban areas. By countries' own definitions, about 30% of the world's people were urban in 1950 and about 55% in 2018, and the UN projected about 68% by 2050 (World Urbanization Prospects 2018). Urbanization is fastest today in Africa and Asia.
Why it works
Cities grow three ways: people move in from the countryside (rural-to-urban migration, pulled by jobs and services and pushed by too little farmland), people are born there (natural increase), and villages at the edge grow until they are counted as part of the city (reclassification). The first agricultural revolutions and industry made this possible: when fewer farmers can feed everyone, most people can work in cities.
| Urban share | Note | |
|---|---|---|
| World, 1950 | about 30% | UN, World Urbanization Prospects 2018 |
| World, 2018 | about 55% | The same source; countries' own definitions of "urban" |
| World, 2050 (projection) | about 68% | Most of the growth in Asia and Africa |
Ways of counting change the answer. The UN's 2025 report used a new, uniform method (the "Degree of Urbanisation"), which counts a city as all the continuous dense settlement around it. By that method, Jakarta (nearly 42 million), Dhaka (almost 40 million) and Tokyo (about 33 million) were the largest in 2025. Older lists, built from each country's own boundaries, put Tokyo first. When you compare city sizes, check the source and the year.
Worked example: Compute the urban share
A country has 40 million people, and 26 million live in urban areas. What percent is urban?
- Urban share = urban population ÷ total population.
- $26 \div 40 = 0.65$.
Answer: 65%.
Worked example: Size or share?
Country A's cities grew from 5 to 6 million people while its total grew from 10 to 15 million. Did A urbanize?
- Before: $5 \div 10 = 50\%$ urban.
- After: $6 \div 15 = 40\%$ urban.
- The cities got bigger, but the share fell.
Answer: No. Its urban share fell from 50% to 40%, even though cities grew.
Common mistake
Thinking the largest cities are in rich countries. Most of today's largest and fastest-growing cities are in Asia and Africa. Many rich countries are already highly urbanized, so their urban share changes slowly.