Lake Simcoe in the context of "Lake Couchiching"

Yonge Street (/jʌŋ/ YUNG) is a major arterial route in the Canadian province of Ontario connecting the shores of Lake Ontario in Toronto to Lake Simcoe, a gateway to the Upper Great Lakes. Ontario's first colonial administrator, John Graves Simcoe, named the street for his friend Sir George Yonge.

Once the southernmost leg of provincial Highway 11, linking the provincial capital with northern Ontario, Yonge Street has been referred to as "Main Street Ontario". Until 1999, the Guinness Book of World Records repeated the popular misconception that Yonge Street was 1,896 km (1,178 mi) long, making it the longest street in the world; this was due to a conflation of Yonge Street with the rest of Ontario's Highway 11. The street (including the Bradford-to-Barrie extension) is only 86 kilometres (53 mi) long. Due to provincial downgrading in the 1990s, no section of Yonge Street is marked as a provincial highway.

The Golden Horseshoe (French: Fer à cheval doré) is a secondary region of Southern Ontario, Canada, which lies at the western end of Lake Ontario, with outer boundaries stretching south to Lake Erie and north to Lake Scugog, Lake Simcoe and Georgian Bay of Lake Huron. The region is the most densely populated and industrialized in Canada. Based on the 2021 census, with a population of 7,759,635 people in its core and 9,765,188 in its greater area, the Golden Horseshoe accounts for over 20 percent of the population of Canada and more than 54 percent of Ontario's population. The population of the greater area is estimated to have exceeded 11,000,000 people in 2024. The Golden Horseshoe is part of the Quebec City–Windsor Corridor, itself part of the Great Lakes megalopolis.

The core of the Golden Horseshoe starts from Niagara Falls at the eastern end of the Niagara Peninsula bordering the United States via New York and extends west, wrapping around the western end of Lake Ontario at Hamilton and then turning northeast to Toronto (on the northwestern shore of Lake Ontario), before finally terminating at Clarington in Durham Region. The term Greater Golden Horseshoe is used to describe a broader region that stretches inland from the core to the area of the Trent–Severn Waterway, such as Peterborough, in the northeast, to Barrie and Lake Simcoe in the north, and to the Grand River area, which includes cities such as Brantford and Guelph, to the west. The extended region's area covers approximately 33,500 km (13,000 sq mi), out of this, 7,300 km (2,800 sq mi) or approximately 22 percent of the area is covered by the environmentally protected Greenbelt. The Greater Golden Horseshoe forms the neck of the Ontario Peninsula.

The name of Toronto has a history distinct from that of the city itself. Originally, the term "Tkaronto" referred to a channel of water between Lake Simcoe and Lake Couchiching, at what is now the city of Orillia, on maps as early as 1675 but in time the name passed southward, and was eventually applied to a new fort at the mouth of the Humber River. Fort Toronto was the first European settlement in the area, and lent its name to what became the city of Toronto.

John Graves Simcoe identified the area as a strategic location to base a new capital for Upper Canada, believing Newark to be susceptible to American invasion. A garrison was established at Garrison Creek, on the western entrance to the docks of Toronto Harbour, in 1793; this later became Fort York. The settlement it defended was renamed York on August 26, 1793, as Simcoe favoured English names over those of First Nations languages, in honour of Prince Frederick, Duke of York. Residents petitioned to change the name back to Toronto, and in 1834 the city was incorporated with its original name. The name York lived on through the name of York County (which was later split into Metropolitan Toronto and York Region), and continues to live on through the names of several districts within the city, including Yorkville, East York, North York, and York the last three being suburbs that were formally amalgamated into the "megacity" of Toronto on January 1, 1998.

The Regional Municipality of York, also called York Region, is a regional municipality in Southern Ontario, Canada, between Lake Simcoe and Toronto. The region was established after the passing of then Bill 102, An Act to Establish The Regional Municipality of York, in 1970. It replaced the former York County in 1971, and is part of the Greater Toronto Area and the inner ring of the Golden Horseshoe. The regional government is headquartered in Newmarket.

As of the 2021 census, York Region's population was 1,173,334, with a growth rate of 5.7% from 2016. The Government of Ontario expects its population to surpass 1.5 million residents by 2031. The three largest cities in York Region are Markham, Vaughan and Richmond Hill.

The zebra mussel (Dreissena polymorpha) is a small freshwater mussel, an aquatic bivalve mollusk in the family Dreissenidae. The species originates from the lakes of southern Russia and Ukraine, but has been accidentally introduced to numerous other areas and has become an invasive species in many countries worldwide. Since the 1980s, the species has invaded the Great Lakes, Hudson River, Lake Travis, Finger Lakes, Lake Bonaparte, and Lake Simcoe. The adverse effects of dreissenid mussels on freshwater systems have led to their ranking as one of the world's most invasive aquatic species.

The species was first described in 1769 by German zoologist Peter Simon Pallas in the Ural, Volga, and Dnieper Rivers. Zebra mussels get their name from a striped pattern commonly seen on their shells, though it is not universally present. They are usually about the size of a fingernail, but can grow to a maximum length around 50 mm (2 in). Their shells are D-shaped, and attached to the substrate with strong byssal fibers, which come out of their umbo on the dorsal (hinged) side.

The Trent–Severn Waterway is a 386-kilometre-long (240 mi) canal route connecting Lake Ontario at Trenton to Georgian Bay, Lake Huron, at Port Severn. Its major natural waterways include the Trent River, Otonabee River, Kawartha Lakes, Lake Simcoe, Lake Couchiching and Severn River. Its scenic, meandering route has been called "one of the finest interconnected systems of navigation in the world".

The canal was surveyed as a military route, but the first lock was built in 1833 as a commercial venture. This connected a number of lakes and rivers near the centre of the waterway, opening a large area to navigation by steamship. The government had begun construction of three additional locks when the Upper Canada Rebellion of 1837 broke out. This led the government to re-examine the project, concluding that the route would have too many locks to allow rapid movement for military purposes. They decided that the locks under construction would be completed, but the rest could be turned into timber slides. This left the completed inland section with no outlet, which business interests addressed by connecting to the route with a number of new toll roads, plank roads, and later, railways.

The Holland River is a river in Ontario, Canada, that drains the Holland River watershed into Cook's Bay, the southern extremity of Lake Simcoe. The river flows generally north, and its headwaters lie in the Oak Ridges Moraine. The Holland River watershed is approximately 600 square kilometres (230 mi), spanning an area that includes New Tecumseth, King Township, Newmarket, Aurora, East Gwillimbury, and Whitchurch-Stouffville. The river's watershed also contains the Holland Marsh, a fertile farmland region renowned for its vegetable production.

The river was originally known as Micicaquean Creek, its indigenous name. It was renamed by Lieutenant-Governor Simcoe after Captain Samuel (Johannes) Holland, (1729–1801), Dutch-born first Surveyor General of British North America.