100 years of US routes: 1926-2026
US 168 was an original 1926 route; the preceding image is from AASHO's Apr. 1927 route log. Its east terminus was in Mt. Vernon, and the west endpoint was in Louisville. US 168 lasted only about seven years: in 1934, US 150 was extended eastward, and it subsumed the entirety of what had been US 168.
Research and/or image credits: Dale Sanderson; Michael Summa