In the Greater Toronto Area, there are 25 incorporated municipalities in either York Region, Halton Region, Peel Region, Durham Region or Toronto. According to the 2021 census, the Greater Toronto Area has a total population of 6,711,985.
| Census subdivision | Municipal status | Total population 2011[1] | Population density 2011 | Total population 2016[2] | Population density 2016 | Total population 2021[3] | Population density 2021 | |
|---|---|---|---|---|---|---|---|---|
| Ajax | Town (lower-tier) | 109,600 | 1,634.2 | 119,677 | 1,786.4 | 126,666 | 1,634.2 | |
| Aurora | Town (lower-tier) | 53,203 | 1,068.8 | 55,445 | 1,112.3 | 62,057 | 1,241.1 | |
| Brampton | City (lower-tier) | 523,906 | 1,967.1 | 593,638 | 2,228.7 | 656,480 | 2,469.0 | |
| Brock | Township (lower-tier) | 11,341 | 26.8 | 11,642 | 27.5 | 12,567 | 29.7 | |
| Burlington | City (lower-tier) | 175,779 | 946.8 | 183,314 | 987.3 | 186,948 | 1,004.4 | |
| Caledon | Town (lower-tier) | 59,460 | 86.4 | 66,502 | 96.6 | 76,581 | 111.2 | |
| Clarington | Municipality (lower-tier) | 84,548 | 138.3 | 92,013 | 150.5 | 101,427 | 166.0 | |
| East Gwillimbury | Town (lower-tier) | 22,473 | 91.7 | 23,991 | 97.9 | 34,637 | 141.4 | |
| Georgina | Town (lower-tier) | 43,517 | 151.2 | 45,418 | 157.8 | 47,642 | 165.6 | |
| Halton Hills | Town (lower-tier) | 59,013 | 213.6 | 61,161 | 221.4 | 62,951 | 227.4 | |
| King | Township (lower-tier) | 19,899 | 59.7 | 24,512 | 73.6 | 27,333 | 82.3 | |
| Markham | City (lower-tier) | 301,709 | 1,419.3 | 328,966 | 1,549.2 | 338,503 | 1,604.8 | |
| Milton | Town (lower-tier) | 84,362 | 232.3 | 110,128 | 303.2 | 132,979 | 366.1 | |
| Mississauga | City (lower-tier) | 713,443 | 2,439.9 | 721,599 | 2,467.6 | 717,961 | 2,467.6 | |
| Newmarket | Town (lower-tier) | 79,978 | 2,086.3 | 84,224 | 2,190.5 | 87,942 | 2,284.1 | |
| Oakville | Town (lower-tier) | 182,520 | 1,314.2 | 193,832 | 1,395.6 | 213,759 | 1,538.5 | |
| Oshawa | City (lower-tier) | 149,607 | 1,027.0 | 159,458 | 1,094.9 | 175,383 | 1,027.0 | |
| Pickering | City (lower-tier) | 88,721 | 383.1 | 91,771 | 396.3 | 99,186 | 383.1 | |
| Richmond Hill | City (lower-tier) | 185,541 | 1,838.0 | 195,022 | 1,928.8 | 202,022 | 2,004.4 | |
| Scugog | Township (lower-tier) | 21,569 | 45.4 | 21,617 | 45.5 | 21,581 | 45.5 | |
| Toronto | City (single-tier) | 2,615,060 | 4,149.5 | 2,731,571 | 4,334.4 | 2,794,356 | 4,427.8 | |
| Uxbridge | Township (lower-tier) | 20,623 | 49.0 | 21,176 | 50.3 | 21,556 | 51.3 | |
| Vaughan | City (lower-tier) | 288,301 | 1,054.0 | 306,233 | 1,119.4 | 323,103 | 1,185.9 | |
| Whitby | Town (lower-tier) | 122,022 | 832.7 | 128,377 | 875.4 | 138,501 | 944.2 | |
| Whitchurch-Stouffville | Town/Municipality (lower-tier) | 37,628 | 182.3 | 45,837 | 222.3 | 49,864 | 241.6 | |
| Total | 6,053,823 | 937.50 | 6,417,124 | 996.54 | 6,711,985 | 1,033.77 |
Inhabitants per km2