(last updated 10/10/2022)
If you are familiar with the mileage signs posted at the terminus points of US 6 and US 20, you might point to those and say, "The answer is plain to see: US 20 is 160 miles longer than US 6."
If both of those signs were accurate, then obviously US 20 would be longer. But the fact is, only one of those signs is accurate, whereas the other significantly overstates the true mileage. I first realized that based on measurements I took in 2016, and later refined in 2020. But you may well be wondering, "Why is the author so certain that '3365' is the figure that is wrong, as opposed to whatever number he came up with?" The answer is because in 2021 the source of the misinformation was identified, when I and others obtained a copy of AASHTO's 1989 route log (that is the most recent version they have published). We learned that the figure of "3365 miles" listed therein was never intended to represent the cross-country mileage of US 20. Let me explain.
One of the many interesting things about this segment of US 34 is that it essentially follows the valley of the Colorado River between its headwaters in Rocky Mountain National Park and its confluence with the Fraser River in Granby. Consequently US 34 also provides access to all of the major water collection components of the Colorado-Big Thompson Project. Those include Grand Lake (Colorado's largest and deepest natural lake) and three artificial impoundments (Shadow Mountain Lake, Lake Granby, and Willow Creek Reservoir). Since there are many examples of highways which were originally built parallel to rivers, but which later had to be realigned because of water storage projects that were built in those valleys, I set out to explore whether US 34 had any historic alignments that existed prior to the reservoirs in the Middle Park area.
Updates and recent changes
US 411[i], US 121[i], US 117[i], Wilson, Wilmington NC, Pee Dee, Florence, US 21, US 170, US 421, US 3, Chattanooga, US 72, US 222, US 541, US 411, US 138, US 119, US 522, Brownsville, US 83 history, US 99, US 51, US 63, US 20, Wilmington DE, Cincinnati, US 22, US 124, US 136, US 150, US 152, US 8, US 264, US 501, US 27, US 104, US 441, Apalachicola, Intra-state routes, Wrong-way overlaps