Regional Municipality of Durham in the context of "Oshawa"

The Greater Toronto Area, commonly referred to as the GTA, includes the city of Toronto and the regional municipalities of Durham, Halton, Peel, and York. In total, the region contains 25 urban, suburban, and rural municipalities. The Greater Toronto Area begins in Burlington in Halton Region to the west, and extends along Lake Ontario past downtown Toronto eastward to Clarington in Durham Region.

According to the 2021 census, the Census Metropolitan Area (CMA) of Toronto has a total population of 6.202 million residents, making it the nation's largest, and the 7th-largest in North America. However, the Greater Toronto Area, which is an economic area defined by the Government of Ontario, includes communities that are not included in the CMA, as defined by Statistics Canada. Extrapolating the data for all 25 communities in the Greater Toronto Area from the 2021 Census, the total population for the economic region included 6,711,985 people.

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.

Steeles Avenue is an east–west street that stretches 77.5 km (48.2 mi) across the western and central Greater Toronto Area in Ontario, Canada. Running from Appleby Line in Milton in the west to the Scarborough-Pickering Townline in the east, where it continues east into Durham Region as Taunton Road, which itself extends 58 km (36 mi) across the length of Durham Region to its boundary with Northumberland County. It is most notable for being the north city limit of Toronto where it borders the southern limit of York Region along its eastern half.

York Region refers to Steeles Avenue as York Regional Road 95 but this use is only internal and there are no signs posted; as the street borders and is maintained by the City of Toronto. Through Peel and Halton Regions, the road is signed as Peel Regional Road 15 and Halton Regional road 8, respectively.

York County is a historic county in Upper Canada, Canada West, and the Canadian province of Ontario. It was organized by the Upper Canada administration from the lands of the Toronto Purchase and others.

Created in 1792, at its largest size, it encompassed the area that presently comprises the City of Toronto, the regional municipalities of Halton, Peel, and York as well as portions of Regional Municipality of Durham and the City of Hamilton. However by 1851, York County only consisted of the areas presently comprising Toronto and Regional Municipality of York. In 1953, York County was split again, with the area south of Steeles Avenue forming the Municipality of Metropolitan Toronto.

Clarington (2021 population 101,427) is a lower-tier municipality in the Regional Municipality of Durham in Ontario, Canada. It was incorporated in 1973 as the town of Newcastle with the merging of the town of Bowmanville, the Village of Newcastle and the townships of Clarke and Darlington, and was established on January 1, 1974. In 1993, the town was renamed Clarington, a blending of the names of the two former townships. Darlington today is largely suburban, while Clarke remains largely rural. Bowmanville is the largest community in the municipality and is the home of the municipal offices.

Clarington is part of the Oshawa census metropolitan area in the eastern end of the Greater Toronto Area (GTA). Major employers in Clarington include the Darlington Nuclear Generating Station, General Motors Canada, and several medium to large-sized manufacturing businesses. Most residents commute for work in Durham Region or Toronto.

The Greater Toronto and Hamilton Area (GTHA) is an urban conurbation that is composed of some of the largest cities and metropolitan areas by population in the Canadian province of Ontario. The GTHA consists of the Greater Toronto Area (GTA) and the City of Hamilton. Unlike the Golden Horseshoe, which covers a larger area, the GTHA specifically refers to the urban conurbation of these regions. Despite not being in the conurbation's name, it also includes the City of Oshawa and its sub-metropolitan area. The GTA is Canada's most populous metropolitan area that includes the core City of Toronto and the regional municipalities of Halton, Peel, York, and Durham (which contains Oshawa). The GTHA forms the core of a larger urban agglomeration known as the Golden Horseshoe.

Beginning in the late-2000s, the term "Greater Toronto and Hamilton Area" was introduced by a few public bodies to refer to the GTA and the city of Hamilton as a single entity. The population of the combined area was 7,281,694 people as of the 2021 census and was estimated to be 8,302,789 as of 2024. The main series of roadways that connects all the areas together (going from Durham to Hamilton) includes highways 401, 427, 403, and the Queen Elizabeth Way. The GTHA has regional public transport served by GO Transit and local service by multiple agencies, which mostly use the Presto card as fare payment.

Lake Scugog is an artificially flooded lake in Scugog, Regional Municipality of Durham and the unitary city of Kawartha Lakes in central Ontario, Canada. It lies between the communities of Port Perry and Lindsay. The lake has been raised and lowered several times over its history. Though not technically part of the Kawartha lakes due to its shallow depths, it is often geographically linked to them. Its sole outflow, the Scugog River, connects to Sturgeon Lake. Lake Scugog is in the Great Lakes Basin and forms part of the Trent–Severn Waterway.