History
On July 1, 1867, four provinces of British North America were united by what is now called the Constitution Act, and the Dominion of Canada was formed. Upper Canada became Ontario and John Sandfield Macdonald its first premier. the industrialization of Ontario began in the mining, forestry and hydroelectric sectors, and in the first decade of the new century, cheap electricity and high national tariffs promoted Ontario's rapid industrialization. From 1896 to 1914 European immigration brought Germans, Scandinavians, Poles, Russians, Ukrainians and Italians to diversify the province's ethnic base.
In the First World War Ontario's factories nearly doubled in size in order to produce material needed to fight the war. During the boom years of the 1920s the province expanded into the manufacture of automobiles, appliances, radios and newsprint. Along with the rest of the Western world, the economy of Ontario collapsed in the 1930s. World War II brought on shortages and rationing as goods were diverted to the war effort. A wave of European immigration into the urban areas followed the end of the war.
Today Ontario is Canada's most populous province, the seat of its federal government and its manufacturing and mining center - nearly 50 percent of Canada's exports originate in the province. As befits an area whose name derives from the Iroquois word for "beautiful lake," Ontario is an international vacation destination whose lakes and forests beckon those seeking pastoral recreation, while its sophisticated and ethnically diverse cities entice others seeking artistic and cultural diversion.

Geography
Ontario is Canada's second largest province. It measures 1680 kilometres (1044 mi.) north to south, and 1609 kilometres (1000 mi.) east to west. Traditionally, Ontario consists of two parts divided along the french and Mattawa rivers from Georgian Bay northeast to mattawa. North of the line is a virtually untouched vastness of nature; south is the Ontario that shelters most of the industry and seven-eighths of the population.
The south is characterized by its seemingly endless shoreline; all of the Great Lakes except Lake Michigan have their northern frontage in this region. This is a low-relief area, with slight rises south of Georgian Bay and in the southern part of the Canadian Shield, a vast expanse of Precambrian rock that underlines most of Ontario. Elevations reach 640 metres (2100 ft) at Tip Top Hill and Mount Batchawana near northern and eastern Lake Superior.
Water is everywhere in Ontario, especially in the southern portion where most rivers and streams are tributaries of the St. Lawrence. River systems in the north include the Moose, Albany. Attawapiskat, Winisk and Severn.
About 250,000 lakes constitute a total water area of 178,074 square kilometres (68,750 sq. mi.) an expanse roughly the size of the state of Missouri. Among the largest interior lakes are Lake of the Woods, Lac seul and lakes Nipigon, Nipissing, Simcoe and St. Clair. Most significant to Ontario are four of the five Great Lakes - Superior, Huron, Erie and Ontario.
The St. Lawrence Seaway is aided by man-made features: the St. Lawrence, Welland and Sault Ste. Marie canals. The Trent-Seven Waterway System connects Lake Ontario with Lake Huron and Geotgian Bay; the Rideau Waterway links the Ottawa River with Lake Ontario. Water falls proliferate in this region, with the 54-metre (176 ft) Niagara claiming supremacy.
Better known island groups include the Thousand Islands of the St. Lawrence, the 30,000 Islands of georgian Bay and neighboring 2792 square-kilometres (1078 sq. mi.) Manitoulin Island, believed to be the world's largest freshwater island.