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Old US 101; the San Juan Grade

While researching maps for California State Route 183 I noticed something interesting on the 1935 Division of Highways editions for San Benito County and Monterey County.  From what it appeared it seems that there used to be a state highway running from US 101 south on San Juan Highway, through San Juan Bautista, south over the San Juan Grade to Salinas.  It turns out what I discovered was an a very old alignment of US 101 in the Gabilan Range which was replaced by 1932.


The information relevant to the history of US 101 over the San Juan Grade is as follows:

-  The San Juan Grade was built in 1915 which replaced Old Stage Road (the route of El Camino Real) from Salinas to San Juan Bautista.  The San Juan Grade was meant to be a replacement route in the Gabilan Range as part of Legislative Route 2 which was defined during the 1909 First State Highway Bond Act.  This construction of the bypass route of the San Juan Grade can be seen on the October 1931 edition of the California Highways and Public Works Journal and on CAhighways.org Legislative Route 2 page.




-  By 1926 the San Juan Grade became part of US 101.  The San Juan Grade alignment can be seen clearly on the 1930 Division of Highways State Map.



-  The San Juan Grade was replaced by 1932 (the 1931 Department Public Works Guide projected the replacement route being opened in the summer of 1932) with the modern Prunedale alignment of US 101 to the west at a lower elevation through the Gabilan Range which can be seen on the Division of Highways Map from said year.


-  The San Juan Grade remained a unsigned spur of LRN 2 at least until 1936 when it appears to have been finally relinquished.   The state maintained roadways on the San Juan Grade are apparent on the 1935 San Benito County and Monterey County Division of Highways maps while it no longer present on the 1936 Division of Highways State map.

1935 San Benito County Map


1935 Monterey County Map


1936 State Highway Map

For comparison sake I prepared a series of maps which shows the historic transportation corridors around San Juan Bautista.  The San Juan Grade is displayed on the maps below in red.






So with that all in mind I was in perfect position to travel the San Juan Grade having just clinched CA 25 since it was directly on my path to Monterey.  I got off US 101 at the CA 129 exit and turned east onto San Juan Highway.





Really there isn't much to San Juan Highway, it is a adequately maintained roadway which travels the farmlands north of San Juan Bautista.


Entering San Juan Bautista US 101 would have utilized 1st Street, Monterey Street, 3rd Street, and The Alameda through the city.  San Juan Bautista has been around since the late 1790s and was founded around the mission bearing the same name on El Camino Real.






US 101 would have continued south of modern CA 156 along The Alameda which is now the north terminus of County Route G1.  G1 quickly branches off of The Alameda onto San Juan Canyon Road which climbs up to Fremont Peak.  The Alameda branches off onto Old Stage Road and San Juan Grade Road; US 101 used the latter.







It quickly becomes apparent that the asphalt on the San Benito County side of the San Juan Grade is just a patch job for very ancient concrete.  The road deck feels suspiciously like the Old Ridge Route (former US 99/LRN 4), I would speculate that it is likely original concrete to US 101.


Although the San Juan Grade is initially straight it quickly becomes curvy.



The actual grade of the San Juan Grade is pretty shallow but very mountainous.  There are plenty of sharp curves but nowhere was it really apparent that two vehicles couldn't pass each other at slow speed.






Near the county line the San Juan Grade peaks out at about 1,050 feet above sea level.  The modern US 101 routing to the west peaks out at about 550 feet above sea level.


The Monterey County Line isn't marked but it is very apparent when the San Juan Grade becomes fully asphalted.




The Monterey side of San Juan Grade is also curvy but the new surface blunts the ominous vibe the San Benito side has.




The San Juan Grade eventually straightens out and heads towards Main Street in Salinas.  I didn't find anything really meriting a picture past Crazy Horse Canyon Road.  I find it weird that such a historic highway segment virtually is unknown much less doesn't have signage indicating it was once part of one of the greatest US Routes that ever existed.


Update October 2019:  It should be noted the northbound lanes of US 101 through Prunedale is the 1932 alignment of the highway.  US 101 northbound from Prunedale passes by a formation called "The Rocks" upon entering San Benito County.  Eventually US 101 was widened to four-lanes but the alignment of the northbound lanes today essentially is the same as it passes The Rocks as it was when it opened in 1932.   In the first photo below modern US 101 northbound at The Rocks can be seen.  In the second photo US 101 is seen at The Rocks as a two-lane highway in 1932.



Comments

Jim Grey said…
I love to see original pavement, especially concrete! I get you totally on the ominous feel you can get on a remote patched-up concrete road. Fresh asphalt means civilization.
Challenger Tom said…
^^^

Really that was a pretty cool find that I honestly didn't know was there until this past week. I noticed the older alignment a couple months back on the 1935 San Benito County map but didn't realize that it was the original US 101 on the San Juan Grade. Either way it kind of makes me wonder if the Ridge Route really could be salvaged as a passable route if the slides were cleared off it. That concrete was in great shape for as old as it really is, totally bumpy, but totally passable still.
Unknown said…
Back in the early 1970s, several of us had to take a make-up class for driver's ed after school. The teacher chose me to drive to San Juan Bautista on that road. I was terrified! I still don't like to drive it.
Wonder Wanda said…
Thanks for visiting SJB again. The "very ancient concrete'' you refer to undoubtedly came from the Old Mission Portland Cement Company (which later became the Ideal Cement Plant), located at the mouth of San Juan Canyon (closed and dismantled in the 70s). This road is used more and more as a result of satellite navigation; I had to pull over once for an errant oncoming semi I saw approaching in the distance. ~ San Juan Bautista Historical Society.
Joel Klein said…
Thanks for this! We did a cycling loop last weekend starting in San Juan Bautista, went up to the top of Fremont Peak, and then did a loop up Salinas Road / San Juan Grade, across Crazy Horse Canyon Road, and back through Aromas. We were wondering about the provenance of the "very ancient concrete paving" of Salinas Road. It seemed odd for an ancient little country road, but makes total sense as a former major highway.
Paul Elliot said…
I have ridden over San Juan Grade a few times by motorcycle and find it to be quite interesting. Sadly, the original Old Stage Road is no longer drivable, but still exists as a hiking and biking trail.

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