Chalifour, J. E. Ontario Manitoba Boundaries [map]. 1:6,336,000. In: Dept. of the Interior. Atlas of Canada Revised and Enlarged Edition. [Ottawa]: Dept. of the Interior, 1915, p.62.

This map shows the complicated stages through which the boundaries of Manitoba evolved. The Earl of Selkirk’s grant is shown, and the boundaries of Manitoba as they were when the Province was created in 1870. The boundary revisions of 1877 indicated on this map are incorrect, because the boundary was only shifted a few miles from the astronomical line to the nearest section survey line, so that the land area did in fact not change significantly. In 1881 Manitoba was enlarged to include the area occupied by immigrant farmers to that date. Basing its case on territorial arrangements made in various early treaties between England and France and at a later time in specific Imperial Acts, the Dominion government in 1881 also attempted to extend the Manitoba boundary eastward to Lake Superior, over the rival claims and protests of Ontario. Ontario won the ensuing dispute and Manitoba had to wait until 1912 to grow in size. Its boundaries were finally extended in that year, but this time northwards to the Bay, into territory where there were no strong counter claims from neighbouring provinces. Ontario Manitoba Boundaries (1915) (Warkentin and Ruggles. Historical Atlas of Manitoba. map 63, p. 164)

Map shows the following boundaries: Boundary of Quebec according to Imperial Act of 1774 Boundary of Grant to Lord Selkirk 1811 Boundary of Manitoba according to Dominion Act of 1870 Boundary of Manitoba according to Dominion Act of 1877 Boundary of Manitoba according to Dominion Act of 1881 (claim of Dominion)