Size Comparison of the UK’s 30 Most Populous Urban Areas

In UK census terms, an urban area refers to any contiguous stretch of “irreversibly urban” land. By ONS definition, a built-up area must be at least 20 hectares (200,000 m²) in size, and any smaller gaps under 200 m are bridged and treated as part of the same built-up zone. In practice this means towns or cities that nearly touch each other form one larger urban area. For example, settlements like London and Reading will count as a single built-up area only if the green space between them shrinks below 200 m.

Using 2011 census data, the 30 most populous built-up areas in the UK (population over 100,000) are as follows. (For brevity, the table lists only total population and land area; most areas have densities around 3,000–4,500 people per km² by this definition.)

Rank	Urban Area (BUA)	Population (2011)	Area (km²)
1	Greater London	9,787,426	1,737.9
2	Greater Manchester	2,553,379	630.3
3	West Midlands	2,440,986	598.9
4	West Yorkshire	1,777,934	487.8
5	Greater Glasgow	957,620	368.5
6	Liverpool	864,122	199.6
7	South Hampshire	855,569	192.0
8	Tyneside (Newcastle area)	774,891	180.5
9	Nottingham	729,977	176.4
10	Sheffield	685,368	167.5
11	Bristol	617,280	144.4
12	Belfast (N. Ireland)	595,879	960.0
13	Leicester	508,916	109.4
14	Edinburgh	482,270	125.0
15	Brighton & Hove	474,485	89.4
16	Bournemouth–Poole	466,266	131.0
17	Cardiff	447,287	102.3
18	Teesside (Middlesbrough)	376,633	108.2
19	Stoke-on-Trent	372,775	103.9
20	Coventry	359,262	81.3
21	Sunderland	335,415	137.5
22	Birkenhead (Wirral area)	325,264	88.2
23	Reading	318,014	83.7
24	Kingston upon Hull	314,018	82.6
25	Preston	313,322	82.4
26	Newport (S. Wales)	306,844	84.2
27	Swansea (S. Wales)	300,352	87.6
28	Southend-on-Sea	295,310	71.8
29	Derby	270,468	64.1
30	Plymouth	260,203	59.7

The map below, created by Reddit user jesus_stalin shows these areas in geographic context. Greater London (in the southeast) clearly dwarfs the rest, with nearly 9.8 million people over ~1,738 km². Most other areas are much smaller: Manchester’s conurbation has ~2.55 M, Birmingham (West Midlands) ~2.44 M, Leeds/Bradford (West Yorkshire) ~1.78 M, etc.

For perspective, London’s built-up area had about 5,630 people per km² in 2011. That is actually quite high by world-city standards. Tokyo–Yokohama (37.8 M people, 8,775 km²) averaged roughly 4,300/km². Paris’s urban area (~11.1 M, 2,854 km²) is about 3,900/km². By contrast, sprawling American metros are much less dense: New York’s 2011 built-up area (~21.4 M, 11,344 km²) works out to only 1,900/km², and Los Angeles (~15.6 M, 6,918 km²) about 2,250/km². In other words, London’s urban core is actually denser than Tokyo or Paris, and far denser than New York or LA – even though its total population is smaller than Tokyo’s.

What do you think? Drop a comment below to share your thoughts on Britain’s biggest cities and how they compare globally.