the highway once extended even farther to the quebec boundary 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 downgraded. the trans-canada highway designation now extends along all of highway 417.