Who was the prime minister of Canada at the time of the transcontinental railroads completion?
Since this question was posted in the Canadian History section, I assume you’re referring to the first Canadian transcontinental railway, the Canadian Pacific. The Last Spike was driven on 7 November 1885, at Craigellachie, British Columbia. During this time, Sir John A. Macdonald was Prime Minister (his second stint in office, for four terms).