The Orphaned US Routes: 4 US Highways With a Decommissioned Parent Route

The United States Numbered Highway System, or simply US Route System, is a network of roads across the US. They were the successor to the Auto Trail system, which itself was a mixture of public and private roads, and not necessarily coordinated with one another. The most famous example of an Auto Trail would be the Lincoln Highway.

The system differs from State Route systems in that the routes connect different parts of the US; US Highway 20 runs from Oregon to Massachusetts, while state routes (typically) remain in their own state. They also differ from the Interstate System in that the vast majority were built in the early 1920's, long before current highway standards were adopted. A US Highway can be a freeway, but a US Interstate cannot be below freeway grade, unless you live in Wyoming. Just like interstates, there are 2-digit and 3-digit US Routes, which relate to their parent route in some way.

As it is much older than the Interstate System, and vast swaths of US Highways have been replaced by interstates, there exists a few 3 digit US Routes that no longer have parents. Today, were going to discuss what they are, and why they were "orphaned".

1) US Highway 138

US 138 is very short by US Highway standards, running between Sterling, CO and Big Springs, NE for about 71 miles. AASHTO guidelines are for state highways to replace US Routes less than 300 miles in length, but given that this runs in more than one state, it survives.

Sanderson image, 2019 via USEnds

So what happened to US 38? Of all the roads in this blog, this one has been orphaned the longest, as US 38 was last signed as such way back in 1931, after just five years in existence. US 38 ran from Greeley, CO to Lincoln, NE, along what is present-day US-6. US 6 underwent a series of extensions from its original alignment to what it is today, now connecting California to Massachusetts. US 6 also replaced a large part of US Route 32.

It's a bit surprising that 138 was never renumbered, as it could have easily been an X-85 or X-34 number. There was also never a US-306 for that matter, but given that it's held the 138 number for over 90 years at this point, it remains fairly permanent. 

The other "orphans" on this blog come from much more significant US Routes, making the fact that 138 has survived for as long as it has that much more remarkable.

2) US Highway 199

US Highway 199 is just slightly longer than US 138, connecting Crescent City, CA with Grants Pass, OR along an 80 mile route.

US-199 in Oregon. Image: Chris Elbert

Like many routes and arterial streets today, 199 started out as a plank road in the 1850's, long before the advent of the US Highway system.

It became an orphan in 1972, after the decommissioning of US Highway 99. I never quite understood the reasoning for decommissioning the route, as large portions of the route are freeway standard. Granted, it's been replaced as a long distance route by I-5, but many US Routes exist side-by-side with their parallel Interstate counterparts. The entire route still exists today as WA-99, OR-99 and CA-99, with historic splits into 99E and 99W as well, so why not bring it back?

199 was saved from becoming a state route itself by connecting two states, as its siblings US-299 and US-399 were decommissioned in 1964, as they only existed within California. Both are now integrated into various California State Routes.

3 & 4) US Highways 166 & 266

Route 66 actually had 7 child routes, including two copies of US 366 at various points in its history. Today, two survive in what I believe is more nostalgia than anything. Both 166 and 266 could easily be decommissioned, as both are far less than 300 miles in length.

US 166 runs for about 163 Miles between South Haven, KS and I-44 west of Joplin, MO, running in the state of Missouri for less than a mile, while multiplexed with another US Route, US 400. Were it truncated to where it connects with US 400, it would lay entirely within Kansas.

US 166 (along with 400 at their Eastern Termini at I-44). Image: Scott Nazelrod, Wikipedia Commons
Like its parent, it once ran all the way into Joplin, but was truncated to its current alignment when I-44 was completed.

US 266 is an even stranger case, as it is just 43 miles in length, and only runs between US-64 in Warner, OK and US-62 in Henryetta, OK, going under I-40, US 66's replacement, without even an interchange. Beginning service in 1926, this replaced OK-9. How this route survived for as long as it did is beyond me, although I think it's unlikely to be decommissioned now, given its association with 66.

Image: Jeff Morrison, 2010 via

The demise of US 66 in conjunction with the creation of I's 40, 44, and 55 is well documented, even in kids movies.

Finally, US 66's highest numbered child, US 666, changed numbers in 2003, after the connotation with the Number of the Beast, combined with an unusually high accident rate among US Routes (mainly because of its poor design through rough terrain) gave it an unfortunate reputation as a dangerous highway. It became present day US Highway 491.


When 491 was converted from US 666 in 2003, a Navajo medicine man blessed the road, hoping to end its "curse". Translated into English, his prayer said ""The road itself never ends. It goes on generation to generation. The new number is a good one. The new road will be a medicine."

Since renumbering change, parts of US 491 are now a 4-lane expressway, and in those stretches where the road has improved, so have accident and fatality rates. (Imagine that) Now, the most dangerous parts of the road are transitions for four lanes into two.

Other Interesting Mentions:
Only the previous four routes exist today while their parents did not, but as the Interstate System replaced US Routes, there exist many examples of child routes that no longer connect to their parents. Probably the most extreme example of this is US Route 310; which connected with its now-truncated parent US 10 at Laurel, MT. All of US 10 west of West Fargo, ND was decommissioned when I-90 was built, leaving its child about 600 miles away.

US 310 in Wyoming, along with WY-789, which was once proposed to be its own US Route. Image:  Jonathan Winkler via
In 1970, AZ-464 and UT-47 got upgraded to US Highway status, becoming US 163. The only problem is the US 63 exists about 900 miles to the east. This was never a child of 63, nor was it ever planned to be, but it's interesting that it was given the 163 number when it connected to US 191. Why couldn't it become 291?

It should be noted that US 163, whatever its number, is an absolutely gorgeous drive, passing through Monument Valley in Utah.

US Route 163 with Monument Valley in the background. Image: Wolfgang Staudt, Wikipedia Commons
And finally, there exist three US Routes with no implied connection to any others; US 400, US 412, and US 425, each of which were more recent additions to the system. US 412 came first in 1982, replacing state routes in Tennessee, Arkansas, Oklahoma and New Mexico. It is located nowhere near US 12, either now or in history.

US 425 came in 1989, replacing AR-13 and LA-137 for 225 miles.

Finally, US 400 was commissioned in 1994 to basically cross the state of Kansas and not much else. A small section of this route was once US-154, before being downgraded to a state route (K-154), which then became a section of US-400. Why not just renumber the entirety US-154 again?

As large and as old as the US Route system is, there is bound to be a few highways which no longer conform to the original rules of the system. For most people, as long as the roads are in good shape, the numbers on the roads don't matter a whole lot, but for those of us who understand the system and its development, discovering the oddities are an interesting hobby.

Thanks as always for reading the blog, and let me know if there's any other US Route anomalies you find interesting!


  1. Enjoyed reading this, thanks. I'll be taking US-50 cross country next fall and looking forward to it.

    1. Thanks for the comment. US 50 has got to be an amazing drive across the country, if very lonely in spots. I can only imagine what the stars look like from rural Nevada.


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