European settlement on Thunder Bay began with two French fur trading posts (1683, 1717) which were subsequently abandoned (see Fort William, Ontario). In 1803 the Montreal-based North West Company established Fort William as its mid-continententrepôt. The fort thrived until 1821 when the North West Company merged with the Hudson’s Bay Company, and Fort William was no longer needed.
By the 1850s, the Province of Canada began to take an interest in its western extremity. Discovery of copper in the Keweenaw Peninsula of Michigan had prompted a national demand for mining locations on the Canadian shores of Lake Superior. In 1849 French-speaking Jesuits established the Mission de l'Immaculée-Conception (Mission of the Immaculate Conception) on the Kaministiquia to evangelize the Ojibwe. The Province of Canada negotiated the Robinson Treaty in 1850 with the Ojibwa of Lake Superior. As a result, an Indian reservation was set aside for them south of the Kaministiquia River. In 1859–60 the Department of Crown Lands surveyed two townships (Neebing and Paipoonge) and the Town Plot of Fort William for European-Canadian settlement.
Another settlement developed a few miles to the north of Fort William after construction by the federal Department of Public Works of a road connecting Lake Superior with the Red River Colony. The work was directed by Simon James Dawson. (see Port Arthur, Ontario) This public works depot or construction headquarters acquired its first name in May 1870 when Colonel Garnet Wolseley named it Prince Arthur's Landing. It was renamed Port Arthur by the CPR in May 1883.
The arrival of the Canadian Pacific Railway (CPR) in 1875 sparked a long rivalry between the towns, which did not end until the amalgamation of 1970. Until the 1880s, Port Arthur was a much larger and dynamic community. The CPR, in collaboration with the Hudson's Bay Company, preferred east Fort William, located on the lower Kaministiquia River where the fur trade
