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California State Route 25; the Airline Highway

Thursday morning brought me back to the Monterey Peninsula.  Given that I hate redoing the same roads repeatedly I decided to take a detour on what I think is one of the most scenic highways in the state; California State Route 25.  CA 25 is a 74 mile north/south highway running from CA 198 north to US 101.  The vast majority of CA 25 traverses the San Andreas Fault which cuts between the Gabilan and Diablo Ranges.  The "Airline" part of CA 25 supposedly comes from the tendency of flight patterns to follow the San Andreas Fault Line.

Generally I don't start off with the historic portion of a highway thread but the former southern terminus of CA 25 on Lewis Creek Road is so bat shit crazy it has to be mentioned.  I started out my day on CA 198 crossing the Diablo Range via Coalinga.  To the west of Priest Valley on CA 198 is a derelict gate on the side of the highway above a canyon.  This gate was the southern terminus of CA 25 at the end of Lewis Creek Road until 1956.

Below CA 198 Lewis Creek Road can be seen following the creek of the same name to the north west.  Lewis Creek Road appears to have never been paved and had numerous fords in it's alignment during it's service history with CA 25.

Today the majority of Lewis Creek Road is a private wilderness area.

Looking east well above CA 198 the craziness of how nuts the southern terminus CA 25 once was comes into stark relief.

CA 25 used to carry Legislative Route Number 119.  LRN 119 was adopted in 1933 and CA 25 was applied to it as part of the original California State Routes in 1934.  What I find really interesting about the southern terminus of CA 25 was that it utilized Lewis Creek when the road south to CA 198 via Lonoak was already built.  This can be seen on the 1935 California Division of Highways Map of Monterey County.  It wouldn't have been unusual at the time for a State Route to be signed over county roads as CA 180 was on Panoche Road at the time which junctions CA 25.

1935 Monterey County Highway Map

The switch from the Lewis Creek alignment to the modern one can be seen on the 1955 and 1956 state highway maps.

1955 State Highway Map

1956 State Highway Map

Descending from the Diablo Range I started CA 25 from the southern terminus at CA 198.  The 51 Miles without services is no joke, coupled with CA 198 from Coalinga its actually 84 miles.

Despite the terrain being relatively flat between the Gabilan and Diablo Ranges CA 25 is a very twisty road which I largely attribute to it straddling the San Andreas Fault.

The first major junction on CA 25 is Lonoak Road in the village of Lonoak.  Lonoak apparently has been in the area since the 1880s and still appears on most maps of Monterey County.  The terrain in Lonoak is lower than the rest of CA 25 and thus coastal fog tends to seep in from Salinas Valley.  Lonoak Road travels west to King City through the Gabilan Range.

North of Lonoak CA 25 crosses Lewis Creek and enters San Benito County.

Immediately after Lewis Creek is the junction with Lewis Creek Road which was CA 25 prior to 1956.  The couple miles of Lewis Creek Road can be driven but you'll eventually come to a ranch gate which blocks access to the dirt segment I mentioned earlier.  The first bridge over Lewis Creek was constructed in 1947.

Traveling north from Lewis Creek Road the next major junction on CA 25 is at Bitterwater Road/County Route G13 in Bitterwater.  G13 isn't signed on the San Benito County side but is on the Monterey side across the Gabilan Range.

North of Bitterwater Road CA 25 approaches Coalinga Road.  Coalinga Road connects with Los Gatos Creek Road in Fresno County and traverses back to the oilfields of Coalinga across the Diablo Range.  I took a crossing of the Diablo Range this winter via Coalinga/Los Gatos Creek Road and it is a wild narrow road with some beautiful views of the mountains.

The next major junction north of Coalinga Road is the San Benito Lateral which travels to a village of the same name.  The community actually predates San Benito County being founded in 1869.  From San Benito the alignment of Old Hernandez Road used to be passable to Coalinga Road.

North of the San Benito Lateral is a recent realignment of CA 25.  I remember this section of roadway back in 2015 when it was largely taken out by a landslide and had one-way traffic control.  I'm honestly not sure why the traffic lights are still up with the replacement road now in place.

Immediately after the road slide realignment the eastern district of Pinnacles National Park can be seen out in the distance.  CA 25 makes a quick descent down to the eastern segment of CA 146 which can be used to access Pinnacles National Park.

North of CA 146 is the junction with La Gloria Road.  La Gloria Road is the northern most road crossing of the Gabilan Range but is almost entirely dirt.  My understanding is that La Gloria Road is well maintained but suffers frequent wash boarding issues given the ranch traffic.

North of La Gloria Road CA 25 cross the San Benito River.

North from the San Benito River the gap between the Gabilan and Diablo Ranges widens.  CA 25 opens up from here and becomes far more populated north to Hollister.

The next major junction on CA 25 is County Route J1 on Panoche Road.  It would seem that Panoche Road was a county maintained portion of CA 180 before 1940 and generally has been part of Caltrans long range plans to update to state highway standards.  J1 will take you east to Mendota and is a very rough road over the Diablo Range.  J1 also marks the location of Paicines which was part of a weird town name exchange in 1873.  Interestingly mileage markers north of J1 along CA 25 used to be post marked for CA 180 which was intended to reach US 101.  It would seem that until the mid-1980s that CA 25 was just a place holder for the future extension of CA 180. has an excellent stub on CA 25 north of J1 being planned as CA 180.

CAhighways on CA 25

The former county level signing of CA 180 along J1 can be seen on the 1938 state highway map.

1938 State Highway Map

North of Paicines and J1 is the community of Tres Pinos.  Originally Tres Pinos was known as Paicines while the community to the south was original Tres Pinos.  Rail service reached modern Tres Pinos in 1873 which was apparently originally promised to go further south.  Apparently the communities switched names in 1874 so it could be said that the railroad actually reached Tres Pinos.  The railroad in question was called the Tres Pinos Branch which was abandoned by the Southern Pacific in 1942.

North of Tres Pinos CA 25 finally reaches Hollister which is the County Seat of San Benito County.  CA 25 becomes a four lane express through Hollister but originally utilized Tres Pinos Road, San Benito Road, Wright Road, and Briggs Road through the city.

North of Hollister CA 25 becomes a two-lane expressway and junctions CA 156.

The expressway north of CA 156 is infamous bad and generally has a series of Jersey Barriers to prevent passing.

After crossing a series of railroad tracks CA 25 enters Santa Clara County and terminates at US 101.  Interestingly there is a Highway 25 Market which in my opinion does a fantastic job emulating the California State Highway mining spade.


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