This is mainly a link farm while I work on putting the sites I have found into a web directory on this domain.
Canoe.ca: Haunted Ontario
The Toronto and Ontario Ghost and Hauntings Research Society
Terry Boyle: Haunted Ontario
The Haunted Walk: Kingston and Ottawa, Ontario.
Burlington Ghost Researchers
Whitby Ghost Walks
Ghost Tours of Niagara
Flickr: Ghosts of the Niagara Region
Canadian Haunters Association
Suite101 by Jason Gray: Tales of Haunted Ontario
Wikipedia: Ghost Towns in Ontario
Abandoned Ontario: Haunted Houses in Ontario
Facebook: Most Haunted Places in Ontario
St. Thomas Elgin Paranormal Society
Facebook: London Ontario Ghost Squad
Paranormal Knights of London
Spirit Matters for Durham Region
CBC Digital Archives: Halloween and Tales of Canadian Ghosts
Paranormal Studies and Investigations Canada
The Halloween Project: Celebrating all things Halloween in Canada.
Canadian Haunters Convention.
Ghost Towns Canada.ca
Ghost Town Pix.com
Haunted Sites in North America: Haunted Sites in Canada by Province