California Highways:
www.cahighways.org

This route was defined in 1958.

Panoche Pass was a well-established crossing of the Diablo Range prior to European contact.  Panoche Road became to come into prominence as the primary highway over the Diablo Range in 1854, following founding of the New Idria Mercury Mine.  The corridor over Panoche Pass would remain the favored route over the Diablo Range to San Joaquin Valley until the Pacheco Pass Highway was rebuilt to state highway standards in 1923. Panoche Road was designated as part of Sign Route 180 in August 1934 when the initial run of Sign State Route was announced.  Despite obtaining a Sign Route designation, the corridor of Panoche Road was never adopted as State Highway and was only partially modernized during the 1940s.  In 1958, County Sign Route J1 was designated over Panoche Road between Sign Route 25 and Little Panoche Road. In 1959, LRN 263 was added to the State Highway System as a planned corridor following the established path of Panoche Road.  Despite being annexed into the legislative definition of Route 180 in 1964, the corridor Panoche Road has never been added to the State Highway System. Panoche Road begins at Route 25 near Paicines in San Benito County, and carries the designation of County Sign Route J1 through the Diablo Range to Little Panoche Road in Panoche Valley.  Panoche Road continues east from Panoche Valley and becomes a dirt highway approaching the ford of Big Panoche Creek.  The dirt segment of this corridor continues into Fresno County passing through the Panoche Hills and Tumey Hills before emerging into San Joaquin Valley at an interchange with I-5.  The remaining 18 miles of Panoche Road east of I-5 to Route 180 near Mendota are comprised of conventional paved highway.
(Source: Gribblenation Blog (Tom Fearer), "Panoche Road and former California State Route 180 over the Diablo Range", 12/25/2025)

Total mileage: 70.48 mi.

According to Tom Fearer (Max Rockatansky) on AAroads in December 2016, Route J1 is deceptive. This route looks pretty good from Fresno County west from I-5 for a couple miles and east from Route 25 in San Benito County but really isn't. This is the second longest signed county route in California at 70 miles only behind County Sign Route J16. County Sign Route J1 basically is falling apart and is in terrible shape, you're in for a hell of a drive if you come this way. County Sign Route J1 gets pretty nasty eastwards after the first one-lane bridge about a half dozen miles from Route 25. Panoche Pass Summit is only 2,250 feet above sea level but the road is in terrible shape getting there. The advertised limit is 55 MPH but 35-45 MPH is really all you ought to be going for in the straights. The pavement is bad enough shape that 20-25 MPH is often necessary in sharp turns. If you're a one-lane bridge fan this is your road.
(Source: Tom Fearer (Max Rockatansky) on AARoads, 12/14/2016)

He also noted: J1 is closely signed to the original proposed alignment of Route 180 west of Mendotta to Route 25. Back in 1938 several maps show Route 180 actually on an alignment to Route 25 via Panoche Road. It would seem that many routes like US 101 in San Francisco, CA 33 in Fresno County, and even parts of Route 49 were actually signed on County/City maintained roadways.
(Source: Gribblenation Blog: County Route J1 11/2017)

• Gribblenation Blog:
  • Signed_County_Route J1
  • Panoche Road and former California State Route 180 over the Diablo Range

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