In the Greater Toronto Area there are 25 incorporated municipalities in either York Region, Halton Region, Peel Region, Durham Region or Toronto.
| City | Population 2006[1] |
Slogan | Mayor |
| Ajax | 90,167 | Ajax by the Lake | Steve Parish |
| Aurora | 47,629 | You're in Good Company | Phyllis M. Morris |
| Brampton | 433,806 | Flower City | Susan Fennell |
| Brock | 11,979 | Larry O'Connor | |
| Burlington | 164,415 | Stand By | Rick Goldring |
| Caledon | 57,050 | Marolyn Morrison | |
| Clarington | 77,820 | Wisdom Knowledge and Trust | Jim Abernethy |
| East Gwillimbury | 21,069 | Thinking Green! | James R. Young |
| Georgina | 42,346 | Robert Grossi | |
| Halton Hills | 55,289 | Rick Bonnette | |
| King | 19,487 | Margaret Black | |
| Markham | 261,573 | The Mark of Excellence | Frank Scarpitti |
| Milton | 53,939 | Gord Krantz | |
| Mississauga | 668,549 | Pride in our past, Faith in our future | Hazel McCallion |
| Newmarket | 74,295 | Prudence | Tony Van Bynen |
| Oakville | 165,613 | Avancez | Rob Burton |
| Oshawa | 141,590 | Prepare to be Amazed | John Henry |
| Pickering | 87,838 | David Ryan | |
| Richmond Hill | 162,704 | En la rose, je fleuris | Dave Barrow |
| Scugog | 21,439 | Marilyn Pearce | |
| Toronto | 2,503,281 | Diversity Our Strength | Rob Ford |
| Uxbridge | 19,169 | Bob Shepherd | |
| Vaughan | 238,866 | The City above Toronto | Maurizio Bevilacqua |
| Whitby | 111,184 | Durham's Business Centre | Pat Perkins |
| Whitchurch-Stouffville | 24,390 | Country close to the city | Wayne Emmerson |