Map of Thunder Bay

Map of Thunder Bay, the largest city in northwestern Ontario, situated at the head of Lake Superior at the mouth of the Kaministiquia River.

Last reviewed on April 27, 2026

About Thunder Bay

Thunder Bay is the regional centre for Northwestern Ontario, a major Great Lakes port handling grain and other bulk cargo, and a hub for forestry and education. The city was formed in 1970 from the merger of Port Arthur and Fort William, and the two former downtowns still function as distinct urban cores.

Geography & Major Routes

Major routes include Highway 11/17 (Trans-Canada) which curves around the city. The Sleeping Giant peninsula across the bay is one of Ontario's iconic landmarks. Kakabeka Falls, the second-tallest waterfall in Ontario, lies to the west.

Thunder Bay Districts & Communities

The Port Arthur core (north end) around Cumberland and Red River Road, the Fort William core (south end) around Victoria Avenue, Bay/Algoma, Westfort, and the Intercity commercial district between the two downtowns are the city’s main areas.

Region

Thunder Bay is part of Northwestern Ontario, with a population of approximately 110,000. For broader context, see the Northern Ontario regional map and the Ontario map with cities.