Ontario, the largest province in Canada, is home to three different landform regions: the Hudson Bay Lowlands (yellow), the Canadian Shield (dark green), and the Great Lakes/St. Lawrence Lowlands (light green).
The most northern region in Ontario, the Hudson Bay Lowlands, is a low area near Hudson Bay and James Bay that is covered with swampy forest. After the last Ice Age much of this land was covered by water. This left a layer of sedimentary rock on top of the Canadian Shield.
The Canadian Shield is the largest landform region in Canada; it covers most of Canada and much of the United States. This region contains some of the oldest rocks in the world (3.96 billion years old). This landform is home to many minerals and metals, thanks to the igneous and metamorphic rock which make up the Canadian Shield. These minerals were placed in the Shield after magma made its way to the surface and deposited them in both the cooling magma and in cracks in the rock, creating high concentrations good for mining. The minerals settled based on density, lighter minerals on top and denser ones below. Many cities and towns are located in the Canadian Shield for the mining such as Sudbury, Timmins, and Cobalt. The hills in the Canadian Shield were once giant mountains that have been ground down over millions of years.
Farther south is the smaller Great Lakes/St. Lawrence Lowlands. It is divided by a piece of the Canadian Shield near Kingston, Ontario. The bedrock of this region was formed by sedimentary rock from the Paleozoic Era. This bedrock can be seen in many escarpments in this region, the best known is the Niagara Escarpment that was formed by differential erosion. The topography of this region varies greatly as glaciers created many hills and valleys as they moved over the land. Glacial hills and valleys surround many flat plains in this region. The climate and the soils make this region excellent for agriculture. The flat land is also good for transportation routes. The Great Lakes/St. Lawrence Lowlands are the most densily populated landform region in Canada because of this and home to many of the countryŐs largest cities, such as Toronto and Hamilton. Much of CanadaŐs industry is also based in this region because of itŐs proximity to transportation routes.