California SR 172 - almost a mile high

[M3100]

(I found a previous thread on this highway from 2017).

This semi-circle shaped highway is still one lane (or rather, a highway with no center line), entirely in Tehama County not far from Lassen Park.  The 2010 California DeLorme Atlas lists Mineral Summit at 5264 feet, a 2 ft difference from the posted sign.  There was also a sign alerting drivers that a portion of the road is not plowed in winter.  There were some pavement gaps etc., but no tire-eating potholes.  Not the smoothest road by any stretch.

It was "home" to a few residences and camgrounds, and was a quiet road.

[STLmapboy]

GSV shows a snow not removed here sign in Mineral at the western CA-36 terminus, followed by--you guessed it--a snowbank where the Street View abruptly ends.
Nice write up!

[Max Rockatansky]

I forget, did we as a group really nail down that this was early 36?  I believe we did but I don't recall. 

[Max Rockatansky]

The 1935 Gousha Map doesn't say it outright but it seems 36 was over Mineral Summit:

http://cartweb.geography.ua.edu/lizardtech/iserv/calcrgn?cat=North%20America%20and%20United%20States&item=States/California/California1935b.sid&wid=1000&hei=900&props=item(Name,Description),cat(Name,Description)&style=simple/view-dhtml.xsl

[M3100]

Thanks for posting that - I agree, the "red highway" on that Gousha map follows the route of what is now SR 172.

[Max Rockatansky]

I want to say Mineral Summit more or less is the divide between the Sierra Nevada and the Cascade Range? 

[sparker]

CA 172 was the original route of LRN 29 (aka SSR 36 between Peanut and Johnstonville and CA 7/US 395 between Johnstonville and the NV state line south of Reno Junction).  The present east end of CA 172 is the spot at which LRN 83/SSR 89 diverged northward to the south entrance of Lassen Park.  Later a cutoff (LRN 86) was built from the current west end of CA 172, curving up the hill to a point on LRN 83/SSR 89 about halfway between the original LRN 29 junction and the Lassen Park entrance station.   SSR 36 was relocated to LRN 86 once it was opened, and the "orphan" section of LRN 29 over Mineral Summit was unsigned until after the '64 renumbering, when it became CA 172. 

I want to say Mineral Summit more or less is the divide between the Sierra Nevada and the Cascade Range? 

That's one of the options posited by geographers as that division point, since it more or less is on the divide between the Feather River watershed (represented by Lake Almanor) and tributaries flowing directly west or SW into the Sacramento River.  Other options are Mt. Lassen itself and the ridgelines east and west from its summit, or, farther north, the Pit River -- since it's the only waterway to penetrate the N-S ridgeline completely south of the Klamath -- the ridgeline surmounted on CA 36 at Freedonyer Pass between Susanville and Westwood and which CA 44 crosses on a broad "saddle" near its junction with county A21.  After the Pit River"interruption", it resumes northward, shadowing the east side of CA 89 and merging with Mt. Shasta's east flank before crossing US 97 at Grass Lake Summit and, of course, heading north into Oregon -- with the 2nd interruption provided by the Klamath River.  That ridgeline continues north unabated until the Columbia River Gorge.   Some cartographers, particularly those of Rand McNally, have always considered the range north of the Pit River to be part of the Cascades, but very few have ventured to put either the Sierra or Cascade label on the mountains between Lake Almanor and the Pit River; most seem to place their northernmost Sierra definition south of CA 36.  I'm sure the academic argument will continue long after most of us are pushing up dust! 

[stevashe]

I actually took a drive on CA 172 earlier in the year and took some photos, overall a nice windy road and pretty good drive. The photos start at the western terminus and go east. Apologies for the dirty windshield, hopefully they're still good enough for you guys. 

https://flic.kr/s/aHsmS18khK

[sparker]

I actually took a drive on CA 172 earlier in the year and took some photos, overall a nice windy road and pretty good drive. The photos start at the western terminus and go east. Apologies for the dirty windshield, hopefully they're still good enough for you guys. 

https://flic.kr/s/aHsmS18khK

Fine pictures.  Curious about the "speed limit restricted" sign, which is itself a bit of a malaprop -- is the speed restricted or the speed limit (which, of course, makes no sense whatsoever)?  A simple "reduce speed" sign would be more appropriate -- or, better yet, an actual B&W speed limit sign (having been on 172 a few times, I'd guess about 35-40 mph tops). 

[stevashe]

I actually took a drive on CA 172 earlier in the year and took some photos, overall a nice windy road and pretty good drive. The photos start at the western terminus and go east. Apologies for the dirty windshield, hopefully they're still good enough for you guys. 

https://flic.kr/s/aHsmS18khK

Fine pictures.  Curious about the "speed limit restricted" sign, which is itself a bit of a malaprop -- is the speed restricted or the speed limit (which, of course, makes no sense whatsoever)?  A simple "reduce speed" sign would be more appropriate -- or, better yet, an actual B&W speed limit sign (having been on 172 a few times, I'd guess about 35-40 mph tops).

If you look further into the background of that picture there is a CA typical "35 Zone Ahead" sign which was followed in turn by a normal "Speed Limit 35" sign. I guess they just wanted super-extra-advanced warning since you might not realize you're coming up on a "town" area after having been on a winding road for 6 miles and so supplemented with the two warning signs.