The Greater Toronto and Hamilton Area (GTHA) is a contiguous urban region 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. The GTA is Canada's most populous metropolitan area that includes the city of Toronto and the regional municipalities of Halton, Peel, York, and Durham. The GTHA forms the core of a larger urban agglomeration known as the Golden Horseshoe.

GO Transit is a regional public transit system serving the Greater Golden Horseshoe region of Ontario, Canada. With its hub at Union Station in Toronto, GO Transit's green-and-white trains and buses serve a population of more than seven million across an area over 11,000 square kilometres (4,200 sq mi) stretching from Kitchener in the west to Peterborough in the east, and from Barrie in the north to Niagara Falls in the south. In 2023, the system had a ridership of 56,036,900. GO Transit operates diesel-powered double-decker trains and coach buses, on routes that connect with all local and some long-distance inter-city transit services in its service area.