An urban agglomeration is defined as "a continuous urban spread constituting a town and its adjoining outgrowths, or two or more physically contiguous towns together with or without outgrowths of such towns". An urban agglomeration must consist of at least a statutory town and its total population (i.e. all the constituents put together) should not be less than 20,000.
List
Below is a list of urban agglomerations in the state of Tamil Nadu, with a population of 1 lakh and above based on the 2011 census of India.[1] Cities in bold are declared Municipal corporations.
Ten largest urban agglomerations in Tamil Nadu
| Rank
|
City
|
District
|
Population
2011
|
| 1
|
Chennai
|
Chennai
|
8,696,010
|
| 2
|
Coimbatore
|
Coimbatore
|
2,151,466
|
| 3
|
Madurai
|
Madurai
|
1,462,420
|
| 4
|
Tiruchirappalli
|
Tiruchirappalli
|
1,021,717
|
| 5
|
Tiruppur
|
Tiruppur
|
962,982
|
| 6
|
Salem
|
Salem
|
919,950
|
| 7
|
Erode
|
Erode
|
521,776
|
| 8
|
Tirunelveli
|
Tirunelveli
|
498,924
|
| 9
|
Vellore
|
Vellore
|
481,966
|
| 10
|
Thoothukudi
|
Thoothukudi
|
410,760
|
| 11
|
Dindigul
|
Dindigul
|
292,132
|
| 12
|
Thanjavur
|
Thanjavur
|
290,724
|
| 13
|
Ranipet
|
Ranipet district
|
262,346
|
| 14
|
Sivakasi
|
Virudhunagar
|
234,688
|
| 15
|
Karur
|
Karur
|
233,763
|
| 16
|
Udhagamandalam
|
Nilgiris
|
233,374
|
| 17
|
Hosur
|
Krishnagiri
|
229,507
|
| 18
|
Nagercoil
|
Kanyakumari
|
224,849
|
| 19
|
Kancheepuram
|
Kancheepuram
|
221,749
|
| 20
|
Komarapalayam
|
Namakkal
|
194,992
|
| 21
|
Karaikudi
|
Sivaganga
|
181,347
|
| 22
|
Neyveli
|
Cuddalore
|
178,925
|
| 23
|
Cuddalore
|
Cuddalore
|
173,361
|
| 24
|
Kumbakonam
|
Thanjavur
|
167,098
|
| 25
|
Tiruvannamalai
|
Tiruvannamalai
|
144,683
|
| 26
|
Pollachi
|
Coimbatore
|
135,235
|
| 27
|
Rajapalayam
|
Virudhunagar
|
130,119
|
| 28
|
Gudiyatham
|
Vellore
|
124,274
|
| 29
|
Pudukottai
|
Pudukottai
|
117,215
|
| 30
|
Vaniyambadi
|
Tirupattur
|
116,712
|
| 31
|
Ambur
|
Tirupattur
|
113,856
|
| 32
|
Nagapattinam
|
Nagapattinam
|
102,838
|
