Topics
Bo, 
Sierra Leone
345,988 people lived in Bo in 2025. It is the 1654th largest of the world's 12,138 cities, and the 2nd largest in Sierra Leone.
Like every city on this site, Bo is counted as a built-up area seen from above rather than as a city government's territory. Why that changes the number.
Verified 2026-09-30 · 73 canaries
People · every five years · 1975 to 2050
How Bo grew
Where Bo had 10 people in 1975, it had 45.7 in 2025.
On the UN's projection it will have 460,506 people in 2050. It passed 250,000 people between 2010 and 2015.
projected (after 2025) · how sure the UN is: high moderate low
How to read this: one column every five years, 1975 to 2050; its height is the number of people. Hatched columns are the UN's projection. The thin strip beneath says how sure the UN is of each figure: the stronger the colour, the surer. A blank means the place was not on the UN's list of cities that year.
People · your family's years · 1975 to 2050
Bo through your family’s years
Put in the years your family were born. You’ll see how many people lived in Bo in each of those years, and when each of them turned 30.
Sierra Leone · every city · 2025
Where it is
How to read this: Bo is the dot in colour with a ring around it. The grey dots are the other cities of Sierra Leone in 2025, 11 in all, led by Freetown, 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, Bo covered 46 km², and buildings, roads and other built-up land covered 11 km² of it. That is 32 m² of built-up land for each person, about a square 6 by 6 metres. Since 1975, its built-up land has grown to 5 times its size, and its people are 4.6 times as many.
How to read this: each pale square is the city's whole area, the strong square inside it the part that is built on; one scale for all three, so a bigger square is more land. Hatched is the UN's projection.
Of every 100 people in Sierra Leone
Its share of Sierra Leone
Of every 100 people in Sierra Leone in 2025, 4 lived in Bo, which is 345,988 people.
How to read this: 100 squares stand for everyone in Sierra Leone, one square for every 100th person. Count the coloured ones and you have Bo's share; the grey remainder live somewhere else in the country.
Ranked by people · 2025
Cities of a similar size
In the world, 2025
- 1650 Burhanpur India346,277
- 1651 Galle Sri Lanka346,263
- 1652 Francisco Morato Brazil346,105
- 1653 Ngandajika Democratic Republic of the Congo345,996
- 1654 Bo345,988
- 1655 Safi Morocco345,865
- 1656 Ras Al Khaimah United Arab Emirates345,621
- 1657 Bukalasi Uganda345,288
- 1658 Ngaoundéré Cameroon345,148
In Sierra Leone, 2025
How to read this: the figure in front of a name is where that city stands among the 12,138 cities the UN counted in 2025, and each bar is its people, on one scale per list. Numbers are missing where a city has fewer than 300,000 people and so has no page of its own.
Apparatus
Sources and method
The figures for Bo 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 Bo 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