Ontario
| Municipality | Population | Joined | Corporate Milestone | Community Milestone | Documentation |
| Ajax (Town) | 91,000 | July 2010 | 0 | 0 | |
| Barrie | 103,710 | March 2001 | 3 | 3 | Action plan |
| Brantford | 86,417 | July 1996 | 0 | 0 | |
| Brockton | 9,658 | September 2007 | 0 | 0 | |
| Brock (Township) | 11 979 | September 2009 | 3 | 3 | Inventory and Action plan |
| Burlington | 150,836 | June 2002 | 1 | 1 | Inventory |
| Caledon | 39,975 | September 2003 | 2 | 3 | |
| Cambridge | 126,748 | April 2012 | 0 | 0 | |
| Cobourg (Town) | 18,210 | February 2011 | 0 | 0 | |
| Collingwood | 16,039 | July 1998 | 2 | 2 | |
| Durham (Regional Municipality) | 531,000 | October 2008 | 0 | 1 | |
| East Gwillimbury | 20,478 | March 2007 | 0 | 0 | |
| Essex (Town) | 20,500 | May 2008 | 0 | 0 | |
| Frontenac (County) | 25,000 | May 2008 | 0 | 0 | |
| Frontenac Islands (Township) | 1,636 | June 2008 | 0 | 0 | |
| Guelph | 106,170 | April 1998 | 3 | 3 | |
| Halton Region | 375,229 | Apri l2005 | 0 | 0 | |
| Halton Hills | 48,184 | April 2001 | 0 | 0 | |
| Hamilton | 662,401 | November 1996 | 4 | 2 | Inventory Action plan - corporate |
| Hearst | 6,000 | June 2006 | 1 | 1 | Inventory |
| Huntsville | 19,056 | April 2012 | 0 | 0 | |
| Kingston | 114,195 | April 2001 | 2 | 2 | |
| Kitchener | 190,399 | January 1997 | 0 | 0 | |
| London | 432,451 | November 1994 | 4 | 4 | |
| Markham | 208,615 | February 2007 | 1 | 1 | Inventory |
| Minto (Town) | 8,165 | May 2008 | 0 | 0 | |
| Mississauga | 700,000 | December 1999 | 3 | 2 | Action plan |
| Newmarket | 65,788 | December 2001 | 0 | 0 | |
| Niagara Region | 435,000 | February 2009 | 1 | 1 | |
| Oakville | 161,500 | June 2004 | 3 | 3 | |
| Oshawa | 156,025 | April 2009 | 2 | 2 | Inventory |
| Ottawa | 774,072 | Februray 1997 | 4 | 4 | Action plan |
| Peel (Region of) | 998,948 | January 2001 | 0 | 0 | |
| Perth | 6,003 | June 1998 | 3 | 3 | |
| Perth South | 4,304 | June 2001 | 0 | 0 | |
| Peterborough | 71,446 | December 2000 | 0 | 0 | |
| Pickering | 94,200 | November 2005 | 3 | 3 | Action plan |
| Port Hope | 15,605 | July 1997 | 3 | 1 | Action plan - corporate |
| Red Lake (Municipality) | 4,600 | May 2010 | 0 | 0 | |
| Richmond Hill | 132,030 | September 2000 | 5 | 3 | Action plan Emissions reductions report - corporate |
| Scugog | 20,173 | January 1997 | 3 | 3 | Inventory and Action plan |
| South Frontenac | 16,415 | December 2000 | 0 | 0 | |
| St. Catharines (City of) | 131,989 | August 2009 | 0 | 0 | |
| Stratford | 29,676 | March 2004 | 3 | 3 | Action plan |
| Sudbury | 155,219 | 1997 | 4 | 4 | Action plan |
| The Blue Mountains | 6,100 | March 2006 | 1 | 1 | |
| Thunder Bay | 109,102 | March 1997 | 3 | 3 | Action plan |
| Toronto | 2,481,494 | 1990 | 3 | 3 | |
| Uxbridge (Township) | 19,169 | September 2009 | 3 | 3 | Inventory and Action plan |
| Vaughan (City of) | 238,866 | April 2011 | 0 | 0 | |
| Waterloo (City of) | 113,100 | June 1999 | 0 | 0 | |
| Waterloo (Regional Municipality) | 525,000 | April 2010 | 3 | 0 | Inventory and Action plan - corporate |
| Wawa (Municipality) | 4,100 | March 2010 | 0 | 0 | |
| Welland | 48,402 | May 2000 | 0 | 0 | |
| Whitby (Town of) | 111,184 | September 2011 | 0 | 0 | |
| Windsor | 208,402 | December 2002 | 1 | 1 | |
| York Region | 889,600 | December 2002 | 3 | 1 | Inventory and Action plan |
Page Updated: 24/04/2012