The geography of Toronto, Ontario, covers an area of 630 km2 (240 sq mi) and is bounded by Lake Ontario to the south; Etobicoke Creek, Eglinton Avenue, and Highway 427 to the west; Steeles Avenue to the north; and the Rouge River and the Scarborough–Pickering Townline to the east. In addition to Etobicoke Creek and the Rouge River, the city is trisected by two minor rivers and their tributaries, the Humber River in the west end and the Don River east of downtown. Both flow southward to Lake Ontario at Humber Bay and Toronto Harbour respectively, which are part of the longer Waterfront, as well as Etobicoke Creek and the Rouge River.

The Toronto ravine system is a distinctive feature of the city's geography, consisting of a network of deep ravines, which forms a large urban forest that runs through most of Toronto. The ravine system is the largest in any city in the world, with the Ravine and Natural Feature Protection Bylaw protecting approximately 110 square kilometres (42 sq mi) of public and privately-owned land. The ravine system has been presented as a central characteristic of the city, with the size of the ravine system leading Toronto to be described as "a city within a park".