Killarney is a municipality located on the northern shore of Georgian Bay in the Sudbury District of Ontario, Canada. Killarney is commonly associated with Killarney Provincial Park, which is a large wilderness park located to the east of the townsite which occupies much of the municipality's expanded boundary. In addition to the community of Killarney itself, the communities of Hartley Bay and Bigwood, and the ghost towns of French River, Collins Inlet and Key Harbour, are also located within the municipal boundaries. The eastern end of the La Cloche Mountain Range is also located within the municipality of Killarney.

Georgian Bay is a large bay of Lake Huron, in the Laurentia bioregion. It is located entirely within the borders of Ontario, Canada. The main body of the bay lies east of the Bruce Peninsula and Manitoulin Island. To its northwest is the North Channel.