The Greater Manchester Built-up Area is an area of land defined by the Office for National Statistics (ONS), consisting of the large conurbation that encompasses the urban element of the city of Manchester and the metropolitan area that forms much of Greater Manchester in North West England. According to the United Kingdom Census 2011, the Greater Manchester Built-up Area has a population of 2,553,379 making it the second most populous conurbation in the United Kingdom after the Greater London Built-up Area. This was an increase of 14% from the population recorded at the United Kingdom Census 2001 of 2,240,230, when it was known as the Greater Manchester Urban Area.

The Greater Manchester Built-up Area is not conterminous with Greater Manchester, a metropolitan county of the same name (and, until 1974, part of the counties of Lancashire, Cheshire and Yorkshire) for it excludes settlements such as Wigan and Marple from Greater Manchester, but includes hinterland settlements which lie outside its statutory boundaries, such as Wilmslow in Cheshire, Glossop in Derbyshire, Whitworth in Lancashire and Newton-le-Willows in Merseyside.

The largest settlements (in descending order of population) within the Greater Manchester Built-up Area are Manchester, Bolton, Stockport, Oldham, Rochdale, Salford, and Bury. These settlements are not coterminous with the Metropolitan Boroughs of the same name, and the ONS takes some of its settlement boundaries within the conurbation from the contiguous urban core of pre-Local Government Act 1972 local government districts. This means that the GMUA bears a much closer resemblance to the earlier "SELNEC" area than to the Greater Manchester Metropolitan County. Unlike most urban areas which expanded outwards around a central core of employment the Greater Manchester Urban Area was formed from the inward expansion of several large manufacturing towns towards a centralised marketplace for the trading of goods and raw materials.

Wigan is separate from the Greater Manchester Built-up Area, although eastern parts of the wider Metropolitan Borough of Wigan, such as Leigh, Tyldesley and Atherton are included. Wigan and Ince-in-Makerfield are included in a separate Wigan Urban Area, which includes places outside Greater Manchester. The gap is formed between Ince-in-Makerfield (of Wigan Urban Area) and Hindley (Greater Manchester Urban Area).

Other built-up areas, including New Mills and the rest of High Peak are narrowly avoided as is Ashton-in-Makerfield (which is included in the Liverpool Urban Area) and much of the parish of Saddleworth.

According to the ONS definitions the Greater Manchester Built-up Area consists of the following settlements:

Rank	Urban subdivision	2011	2001	1991	1981	Extent
1	Manchester	510,746	394,269	402,889	448,604
2	Bolton	194,189	139,403	139,020	143,921
3	Sale	134,022	55,234	56,052	57,933
4	Rochdale	107,926	95,796	94,313	97,942
5	Stockport	105,878	136,082	132,813	136,792
6	Salford	103,886	72,750	79,755	98,343
7	Oldham	96,555	103,544	103,931	107,830
8	Bury	77,211	60,718	62,633	62,181
9	Atherton	70,542	20,302	21,696	22,032
10	Altrincham	52,419	40,695	40,042	39,693
11	Ashton-under-Lyne	45,198	43,236	43,906	44,196
12	Middleton	42,972	45,314	45,621	51,437
13	Urmston	41,825	40,964	41,804	44,030
14	Eccles	38,756	36,610	36,000	37,792
15	Denton	36,591	26,866	37,785	37,724
16	Wilmslow	35,945		28,604	28,933
17	Chadderton	34,818	33,001	34,026	33,518
18	Romiley	34,696
19	Hyde	34,003	31,253	30,666	30,551
20	Glossop	33,020
21	Radcliffe	29,950	34,239	32,567	27,642
22	Heywood	28,205	28,024	29,286	29,686
23	Farnworth	26,939	25,264	25,053	26,148
24	Stretford	46,813	42,103	43,953	47,771
25	Stalybridge	26,482	22,568	22,921	23,668
26	Swinton	25,362	24,183	21,425	18,235
#	Westhoughton	24,974	22,345	15,315	12,525
27	Hindley	24,497	23,457	22,581	21,493
28	Cheadle Hulme	24,362	23,253
29	Golborne	24,167
30	Droylsden	24,134	23,172	22,666	22,624
31	Royton	23,812	22,238	21,475	21,098
32	Newton-le-Willows	22,114
33	Walkden	21,194	36,218	38,685	39,466
34	Gatley	20,997
35	Whitefield	20,975	23,284	22,783	27,650
36	Dukinfield	20,909	18,885	17,917	17,501
37	Irlam	19,933	19,018	18,504
38	Horwich	19,492	18,289	18,017	16,769
39	Hazel Grove	19,365
40	Failsworth	18,844	20,007	20,160	20,951
41	Shaw	18,815
42	Ramsbottom	17,872	17,352	17,318	16,334
43	Bramhall	17,436
44	Hale	16,624	15,316	15,868	16,308
45	Tyldesley	16,142	34,022	30,606	27,903
46	Poynton	15,282	14,038	14,768	15,078
47	Cheadle	13,467
48	Uppermill	13,448
49	Lees	13,062
50	Little Lever	12,803	11,082	11,589	12,062
51	Littleborough	12,370	13,807	13,638	13,787
52	Kearsley	11,150	9,906	9,287	9,666
53	Mossley	10,772		10,569	8,865
54	Milnrow	10,015	12,776	12,541	11,631
55	Worsley	9,108
56	Partington	7,912	7,723	9,109
57	Whitworth	7,500	5,672	5,679	5,682
58	Hadfield	6,305
59	Hattersley	4,825
60	Blackrod	4,548
61	Gamesley	3,263
	Cheadle and Gatley		57,507	58,457	59,828
	Leigh		43,006	43,150	42,929
	Swinton and Pendlebury		41,347	43,155	44,508
	Hazel Grove and Bramhall		38,724	39,730	40,680
	Wilmslow/Alderley Edge		34,087
	Prestwich		31,693	31,801	32,035
	Bredbury and Romiley		28,167	28,205	28,558
	Bromley Cross/Bradshaw		22,747	22,017	21,728
	Shaw and Crompton		19,335	19,348	19,258
	Audenshaw		12,790	13,173	10,771
	Longdendale		8,680	10,890	12,901
	Handforth		8,014
	Tottington		7,545	7,673	6,745
	Wardle		7,092	6,622	2,149
	Brinnington		6,759
	Bowdon		6,079	5,141	4,894
	Alderley Edge			5,280	5,009
	Buckton Vale			3,592	3,457

Notes:

• Geography of Greater Manchester
• List of Greater Manchester settlements by population

• Map showing makeup of the conurbation according to the ONS (PDF)