US 163 was commissioned by AASHO* at their June 1970 meeting. The designation ran from Kayenta AZ on the south up to Crescent Junction UT on the north (illustrated by the green lines on this map):
Pretty amazing coincidence...
Heading west from Portland, US 26 enters the path of totality near Mt. Hood, and remains within the path for about 330 miles, all the way to the Idaho border: