City and inland port in Ontario, Canada, on Lake Superior; population (2006) 103,200. A major exporter of wheat and ore, it marks the westernmost extent for sea-going ships on the St Lawrence Seaway, and is the lakehead terminus of the Canadian National Railway. Industries include tourism, shipbuilding, timber-milling, and the manufacture of wood and metal products, vehicles, farming equipment, paper, and pulp. It was created in 1970 by the union of Port Arthur, its twin city Fort William to the south, and the towns of Neebing and McIntyre.
Local mineral deposits include iron pyrites, molybdenum, feldspar (mined for potash), silica (used in glass-making), silver, lead, copper, zinc, gold, and the largest haematite iron-ore mine in Canada.
Features Thunder Bay is the seat of Lakehead University (1965). Cultural centres include a reconstruction of Old Fort William as an early 19th-century fur-trading post, the Historical Museum, and Thunder Bay Art Gallery. Port Arthur, or Thunder Bay North, contains Little Suomi, the world's largest Finnish community outside Finland; the original settlers arrived in 1872.
History In 1870 troops from eastern Canada disembarked at the site of Port Arthur on their way to quell an Indian rebellion; the spot was named Prince Arthur's Landing after the Duke of Connaught, later governor general of Canada. The town of Prince Arthur was incorporated in 1884. Fort William was established by the British in 1789, and became an outpost of the Northwest Company, which was later replaced by the Hudson Bay Company in 1815. The companies merged in 1820.