Endpoints of
US Route 20[w]

Mileage: in 1989 AASHTO listed a figure of 861 miles for US 20[w]... however, that included the mileage of US 20's associated business route.  According to the state subtotals on AASHTO's 1989 spreadsheet, the actual end-to-end total of mainline US 20[w] at the time was 857 miles.  That closely matches our own 2020 measurement, which yielded 856.8 miles.  Want historic mileages?  Our handy reference book includes the mileages that were published in all 13 of AASHO/AASHTO's historic route logs (spanning the years 1927 to 1989).

US 20 does not exist within Yellowstone National Park, and although the route is implied to run through Yellowstone, the Park divides US 20 into two separate segments.  The east segment was among the original 1926 routes, but the west segment was not commissioned until 1940.  The east end of US 20[w] has always been in West Yellowstone.

Originally US 99E followed the route of the minivan and the pickup visible in the distance: it came in from the right on Salem Avenue, then ahead on Main a block or two, then left on either 1st or 2nd Avenue.  Westbound US 20 came in from the right via Santiam Highway (the road in the foreground), then would have gone ahead one block on Main, ending at the next intersection (Salem), at its junction with US 99E (that intersection has now been reconfigured into a roundabout).  But that endpoint was very short-lived: in the early 1940s, US 20 was extended past Albany, through Corvallis and on to its current western terminus at Newport.  The Oregon DoT must have done that extension without AASHO's approval, because AASHO did not address it until their 1943 meeting, and it appears to have already been in effect:

Research and/or image credits: Ben Bonson, George Bourey; Wayne Brunelle; Nancy Cooper; Chris Elbert; Dan Moraseski; Jeff Morrison; Robert Mortell; Dale Sanderson; Michael Summa; TopHatGuy; Joe Zelinski