The term Carolinian zone is used in Canada to refer to the southernmost part of the province of Ontario, generally considered to lie south of a line drawn between Toronto and Grand Bend, Ontario.
This region is the northern continuation of the deciduous forest region of the eastern United States which extends south to the Carolinas. Besides its southern location, the climate of this area is also moderated by the nearby Great Lakes, so it is able to support animal and plant species usually not found in other parts of Canada. Because the major population centres of Ontario are located nearby, there has been significant loss of wetlands and forested areas to urban areas and farms.
Although this Carolinianzone comprises less than a quarter of one percent of Canada's land area, it is home to more types of flora and fauna than anywhere else in the country.
Carolinian Canada is a cooperative project set up in 1984 by the Province of Ontario and non-profit conservation groups to preserve the ecological diversity of this zone.
The protection of the Carolinianzone continues to be a challenging conservation issue in southwestern Ontario.