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California State Route 25; the Airline Highway

Over the last couple years I've found myself headed out to the Monterey Peninsula frequently.  Given that I'm not exactly a fan of always following a freeway or taking Pacheco Pass I often take a much more scenic route via California State Route 25 the Airline Highway. 

CA 25 is a 74 mile north/south highway running from CA 198 in Monterey County north to US 101 in Santa Clara County.  The vast majority of CA 25 traverses the San Andreas Fault which cuts between the Gabilan Range and Diablo Range.  The "Airline" part of CA 25 comes from the tendency of flight patterns to follow the San Andreas Fault Line.

Part 1; the history of CA 25 and the haggard legend that is Lewis Creek Road

As originally defined CA 25 was routed entirely along Legislative Route 119.  LRN 119 was adopted in 1933 as a new highway between US 101/LRN 2 near Gilroy south to LRN 10 (future CA 198) at Priest Valley.  In an August 1934 California Highways and Public Works Guide CA 119 was defined as being routed over the entirety of LRN 119.

Oddly LRN 119 and CA 25 reached CA 198/LRN 10 via Lewis Creek Road.  Even by the standards of the 1930s the route over Lewis Creek Road was extremely haggard as it forced traffic over numerous earthen fords of Lewis Creek.  At the time the much gentler grade via Peach Tree Road through Lonoak and Peach Tree Valley but was available but for unknown reasons it wasn't adopted by the Division of Highways.  Lewis Creek essentially acts as the Monterey/San Benito County Line.  CA 25/LRN 119 terminating at CA 198/LRN 10 can be seen on the 1935 Division of Highways Maps of San Benito County and Monterey County.

Monterey County

San Benito County

The switch from the Lewis Creek Road alignment to the modern route of CA 25 on Peach Tree Road can be seen on the 1955 and 1956 Division of Highways State Maps.  Of note; starting in 1954 the Division of Highways started charting Lonoak in San Benito County in error.  Lonoak is located within Monterey County at the intersection of CA 25/Peach Tree Road and Lonoak Road.  Even as Lewis Creek Road was being replaced in 1955 it still was a dirt segment of CA 25.

1955 Division of Highways State Map

1956 Division of Highways State Map

Interestingly none of the California Highways and Public Works Guides from the 1950s outright say why CA 25 was moved from Lewis Creek Road to Peach Tree Road.  That said, it appears that floods in December of 1955 caused numerous washouts along CA 25/LRN 119 and CA 198/LRN 10.  These floods and washouts likely rendered Lewis Creek Road unusable as State Highway given that it traversed numerous earthen fords.  The floods in the Diablo Range and Division of Highways District 5 appear in the January/February 1956 California Highway and Public Works Guide.

CA 25/LRN 119 on Peach Tree Road is next referenced in the November/December 1956 California Highways and Public Works Guide as being budgeted for paving operations in 1957-58.

During the 1964 State Highway Renumbering CA 25 north of County Route J1/Panoche Road was reassigned as Legislative Route 180.  This change was made in anticipation of CA 180 being built across the Diablo Range and can be seen on the 1964 Division of Highways State Map.

According to CAhighways the definition of CA 180 was cut back to Paicines and CA 25 was legislatively restored to US 101 in 1984.  The restored legislative route of CA 25 appears for the first time on the 1986 Caltrans State Map.

According to CAhighways the bypass route of CA 25 within Hollister was completed in November 2008.  CA 25 originally utilized; Tres Pinos Road, San Benito Road, Wright Road, and Briggs Road through downtown Hollister.

Part 2; former CA 25 on Lewis Creek Road

The 1934-1955 alignment of CA 25 on Lewis Creek Road is so bizarre that I thought merited mapping out.  In the maps below I plotted the former route of CA 25 on Lewis Creek Road as it before it was relinquished.  Note; I identified two fords of Lewis Creek that were part of CA 25 but no longer are part of modern Lewis Creek Road.

Today the former southern terminus of CA 25 on Lewis Creek Road can be found at CA 198 Post Mile MON 20.513.  Former CA 25 on Lewis Creek Road is gated off as a private reserve.  

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.

The private land signs on former CA 25 on Lewis Creek Road are very apparent.

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

The split in modern CA 25 on Peach Tree Road and Old CA 25 on Lewis Creek Road can be found at a T-Intersection at Post Mile SBT 0.555.  Even in 1933 when LRN 119 was adopted the T-Intersection of Peach Tree Road and Lewis Creek Road still existed much as it does now.  Lewis Creek Road is signed with the distances to certain property owners, the furthest is shown to be about 6 miles to the east of modern CA 25.

Former CA 25 on Lewis Creek Road looking southeast is very striking.  The building on right next to Lewis Creek is known as Tully Hall.

Old CA 25 on Lewis Creek Road quickly crosses Lewis Creek next to Tully Hall on the one-lane 1947 Lewis Creek Bridge.  The 1947 Lewis Creek Bridge is a pony truss span that is 87 feet in length.

Old CA 25 on Lewis Creek Road exists in a grey area of maintenance given it crosses the San Benito/Monterey County Line numerous times.  Lewis Creek Road is listed as San Benito County Road 133.  I'm to understand that despite Lewis Creek Road being maintained by San Benito County that Monterey County frequently clears it.

Old CA 25 on Lewis Creek Road headed southeast is highly scenic but doesn't appear to have access to anything but private property.  Some of the ranches on Lewis Creek Road are long abandoned and in a state of disrepair.

Part 3; a drive on modern CA 25

My drive on CA 25 was from westbound CA 198 after descending the Diablo Range to Peach Tree Valley.  From CA 198 the route of CA 25 north is signed with a "No Services 51 Miles" advisory.  This sign is no joke as coupled with CA 198 west out of Coalinga there is about 90 miles without services. 

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 at Post Mile MON 9.857.  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.

As noted above CA 25 north meets Old CA 25 on Lewis Creek Road at Post Mile SBT 0.555.

Traveling north from Lewis Creek Road the next major junction on CA 25 is at Bitterwater Road/County Route G13 in Bitterwater at Post Mile SBT 7.302.  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 at Post Mile SBT 9.37.  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 at Post Mile SBT 18.099 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 which has eroded away.  Apparently the new road hasn't been repaired due to environmental concerns regarding a rare salamander.

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 SBT 21.47 which can be used to access Pinnacles National Park.

North of CA 146 is the junction with La Gloria Road at Post Mile SBT 26.018.  La Gloria Road is the northern most road crossing of the Gabilan Range but is almost entirely dirt.  La Gloria Road is a well maintained and can be driven by car west towards Gonzales. 

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 approaching Hollister.

The next major junction on CA 25 is County Route J1 on Panoche Road at Post Mile 39.534.  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. 

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.

North of Hollister CA 25 becomes a two-lane expressway and junctions CA 156 at approximately Post Mile SBT 54.036.

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.


Anonymous said…
Hi, the myth that airlines followed the this highway or the fault line has been debunked in Wikpedia:
The Airline Highway Association was organized in 1933-4 and was composed of representatives of Alameda, Santa Clara, San Benito, Kern and Kings Counties. Its purpose was to establish this "Airline Highway". In the Oakland Tribune article, (Tues. June 19, 1934 page 5. "NEW AIRLINE, HIGHWAY TO L.A. PLANNED") it states "the highway would follow the air line between the northern and southern part of the state as closely as possible". The use of the word Airline is confusing as we associate it with modern-day transportation. In this sense it is defined as an Americanism dating back to 1805 meaning "traveling a direct route"

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