During this period, the railway served not just Canada’s largest cities—Toronto, Montréal, Halifax, Saint John—but also the American Northeast, passing through Chicago, Detroit, Buffalo, New York, Boston and Portland. The Grand Trunk also connected to complimentary Canadian and American lines.
This 1878 map shows the eastern provinces, which joined the Confederation starting in 1867: Ontario, Quebec, New Brunswick and Nova Scotia. Prince Edward Island joined in 1873. The western provinces, Manitoba (1870) and British Columbia (1871) are not shown, since the railroad was developed there quite a bit later.