Southwestern Ontario and a narrow strip along the coast of the
Saint Lawrence River are in the
Mixedwood Plains, a fertile and productive
ecozone that is typically flat with rolling hills, and was once covered by forest before its use for
agriculture, and later
urbanization, resulted in
deforestation of vast swaths of the area. To its north is the
Boreal Shield, the largest provincial ecozone, extending from south-central Ontario to cover most of northern Ontario, where it abuts the
Hudson Plains. The
Northwestern Ontario portion of this area is part of the
Midwestern Canadian Shield forests ecoregion of
boreal forest that spreads west through
Manitoba and
Saskatchewan. The plains that cover the heartland of Ontario are a transitional ecozone characterized by boreal features in the south and
tundra landscapes in the north. This extends the entire range of the northern coast of Ontario with
Hudson Bay and
James Bay, at which numerous
wetlands act as
staging and nesting grounds for
migratory birds. The waters of the two bays are in the
Arctic Archipelago Marine ecozone, forming its southern, subarctic extent.
Geology Ontario, owing to its size, has diverse geology that varies in structure, age, and lithology. About 61% of the province is covered by the
Canadian Shield, mostly with
Precambrian rock. These rocks contain large mineral deposits that are vital to the economy of northern Ontario. The shield can further be divided into three sections. The northwestern parts of the Shield, located roughly north and west of Sudbury, are known as the Superior Province; The boundary of Ontario on Hudson and
James Bay does not extend beyond the shoreline, as all islands within the bays belong to
Nunavut. The border with
Quebec is defined by a line due north of the head of
Lake Timiskaming to James Bay, and southeast from there, the
Ottawa River for about . The boundary follows a small portion of land south of the Ottawa River until it meets the
Saint Lawrence River near
Cornwall. Ontario also shares borders with several
U.S. states. From west to east, the
Minnesota border consists of the
Lake of the Woods,
Rainy River,
Rainy Lake and its tributaries. The border then includes the only 1 km of land of its entire 2,700 km U.S. border, the
Height of Land Portage, which divides the
Arctic Ocean and
Nelson River watershed from that of the
St Lawrence River and the
Atlantic Ocean. The U.S./Minnesota border then follows tributaries of the
Pigeon River to its mouth at Lake Superior. Ontario borders
Michigan across
Lake Superior, the
Saint Mary's River,
Lake Huron, the
St. Clair River,
Lake St. Clair, the
Detroit River, and
Lake Erie. The province also borders
Ohio and
Pennsylvania across Lake Erie. The 309 km boundary with
New York includes
Lake Ontario, the
St. Lawrence and
Niagara rivers.
Elevation An extensive amount of land along the south and west shores of
James Bay and
Hudson Bay is low and covered with wetlands. The land in the North-east and North-west, generally north of
Lake Superior, is the
Canadian Shield where most of Ontario's highest points are found. Further south, many hilltops of the Algonquin, Haliburton and Madawaska Highlands, which are also part of the shield that covers much of the north, surpass altitudes of 500 m (1640'). The Municipality of Temagami is located on the northeast arm of Lake Temagami, 100 km north of North Bay. Ontario's highest point, Ishpatina Ridge (693 metres), is within the municipality's boundaries. The next highest points are in
Dufferin,
Grey and the western side of
Simcoe counties, where the elevation ranges from 430 m (1,400') to 540 m (1,750'). Much of the higher land sits atop the
Niagara Escarpment in a generally flat area known as the Dundalk Highlands. Just to the south, in
Wellington County and
Waterloo Region, general elevations are from 300 m (1,000') to 400 m (1,300'). A striking topographical feature of the Niagara Escarpment is its limestone cliff face, in general between 80 m (250') and 100 m (330') above the surrounding land, extending from the Niagara peninsula northwest to the
Bruce Peninsula. The flattest areas of the province can be found in the lowlands of the far north, and in southwestern and eastern Ontario.
Water , one of Ontario's most noted tourist destination and a source for hydroelectricity Ontario is known for the large number of lakes and rivers it contains. Ontario contains more than 250,000
lakes (including those forming part of the
Great Lakes). The Great Lakes are a large binational system shared between Canada and the United States, which hold roughly 20% of the world’s fresh surface water; this figure reflects the volume of the Great Lakes as a whole, not the many smaller lakes across Ontario. Ontario is also known for being the only province in Canada that touches the Great Lakes. Ontario touches four of the Great Lakes:
Huron,
Lake Ontario (the province is named after the lake),
Erie and
Superior. Ontario's vast rivers and lakes originally opened the province for exploration and have made possible hydroelectric power, mills and various forms of industrialization. Most of Ontario is fed by rainfall, and in most parts
snow is relied on. Precipitation is most common in the southern and central parts of Ontario where variations among the seasons are not especially great; but winter and spring are less aqueous than in northern and northwestern Ontario. ==Climate==