The highway once extended even farther to the Quebec border in East Hawkesbury with a peak length of about . However, a section of Highway 17 "disappeared" when the Ottawa section of it was upgraded to the freeway Highway 417 in 1971. Highway 17 was not re-routed through Ottawa, nor did it share numbering with Highway 417 to rectify the discontinuity, even though Highway 417 formed a direct link between the western and eastern sections of Highway 17. However, from East Hawkesbury to Ottawa, Highway 17 retained the Trans-Canada Highway routing and signs until it met up again and merged with Highway 417 until 1997, when Highway 17 through Ottawa was downloaded. The Trans-Canada Highway designation now extends along all of Highway 417.
The route which would become Highway 17 was first designated as a provincial highway on February 26, 1920, when two separate highways were added to the system. The first travelled between Ottawa and Pembroke, while the second travelled between Ottawa and Point Fortune at the... Read More