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New Idria Adventure Route

Updated: Feb 9, 2023

Situated roughly half-way between Los Angeles and San Francisco, the New Idria Adventure Route is the perfect getaway for a quick adventure in an oft overlooked region in Central California. With a wide range of geological and ecological zones, the adventure route provides a unique backcountry experience.



Route Overview

Adventure Rating: Epic

Trip Length: 151 miles, 2 - 4 days

Season: Year round, but the shoulder seasons of Spring and Fall are the best time to visit. BLM closes vehicle access to Tumey Hills from April 15 - October 15 (continue on Panoche Road to I-5 if closed).

Avg Technical Rating: 2

Peak Technical Rating: 3

Typical Terrain: This track is approximately 60% dirt and 40% pavement. Expect mostly well graded dirt roads, some very bump paved county roads, and some steeper and off camber tracks through Clear Creek Management Area.

Recommended Vehicle: 4x4 with all terrain tires. Recommended Gear: n/a

Adventure Vans: Yes! We don't recommend Sprinter 4x4s, as they're likely to have issues through portions of Clear Creek Management Area, especially the off camber section from Mexican Lake to New Idria.

Alternative Routes: n/a Important Info for Gate Codes Permits: The serpentine barrens of Clear Creek Management Area are gated. In order to obtain the gate codes from BLM, you'll need to purchase a vehicle permit and ACEC permit ($16 for both permits as of 2022).

 

Route Details

Situated roughly half-way between Los Angeles and San Francisco, the New Idria Adventure Route is the perfect getaway for a quick adventure in an oft overlooked region in Central California. Despite the lack of attention the area sees, the various roads and trails that make up the route have long been popular with the dual sport crowd. And before Clear Creek Management Area was closed, and ultimately re-opened to the public, it was once one of the most popular OHV parks in Central and Northern California. While the vast majority of the network has since been permanently closed, the unique geological workings that make up the San Benito Mountain area and New Idria mining district are still worth visiting. The serpentine dome (or mass) that makes up San Benito mountain and the surrounding ridges played major roles in quicksilver and asbestos production. The New Idria Mine came into importantance during the 1850s when miners discovered the presence of quicksilver, which was used extensively, and to the environment's detriment to separate gold from crushed ore. In the 20th century, mining companies would lay claim to the asbestos rich soils of San Benito's serpentine mountains and hills. Developed by Union Carbide in 1963, the KCAC mine (King City Asbestos Corporation) quickly became the largest asbestos mine in the world and it, along with other mines in the New Idria mining district helped to triple the United States' asbestos production in a matter of years. As you may expect, all of these mines have since been closed given the health hazards posed by mercury (quicksilver) and asbestos. There was another important mineral that was discovered in these mountains in 1907. One of the world's rarest minerals, Benitoite was discovered a few miles from the massive KCAC mine. Since its discovery, Benoite has been found in other locations across the globe, but only two mines have produced gem-quality Benitoite, both of which are in the New Idria mining district. Unsurprisingly, the mineral is found in hydrothermally altered serpentinite, and presents as a brilliant dark blue to pale blue when cut into a gemstone. Those wishing to hunt for Benitoite gem's should visit the Benitoite Mining Company, which is open to the public (reservations required). While the route can be done in either direction, our route guide begins on La Gloria Road, just outside the town of Gonzalez in the heart of Steinbeck country; the Salinas Valley. Once you reach the Swiss Rifle Club, the road turns to dirt and begins to climb through the hills with fantastic views of the Salinas Valley as you ascend into the mountains. The rolling hills and pastureland along La Gloria Road (DP1) provide a glimpse into Central California's past. Many of the ranches along the road were established over 150 years ago, still making their living the same way they did then; raising cattle. The route jumps onto the pavement of Highway 25 passing Pinnacles National Park before veering back off onto the dirt of Old Hernandez Road (DP2). Old Hernandez Road is quite similar to La Gloria, filled with rolling oak studded hills, pastureland, and tame, wide dirt roads. Pay no mind to the Road Closure signs (we're unclear why they're here, as locals use this road on a daily basis). The road can become impassable after major rain events when the waters of the San Benito River (DP3) may be too high to ford. But most times of year, the water is under a foot deep, making easy work for even low clearance vehicles. Old Hernandez Road eventually meets up with the pavement again, and the route passes a number of developed BLM campgrounds. While developed Laguna Mountain campground certainly has the best views, we prefer the more spread out Sweetwater campground. As you turn off Coalinga Road onto Clear Creek Road, the pavement soon gives way back to dirt. Keep in mind, you'll need the gate code in order to continue east through the locked gate at the entrance of Clear Creek's Area of Criticial Environment Concern (ACEC permit), which can only be purchased online. Upon reaching the east gate, serpentine mountains and barrens (areas with little to no vegetation) come quickly into view. Clear Creek can be seen at the canyon bottom below, directly on your right. You'll cross over Clear Creek and its tributaries many times as route ascends higher into the San Benito Mountains. Long gone are the wide open and graded county roads. The giant serpentine mass that covers much of the Clear Creek Management Area creates a unique landscape, with endemic species that have evolved over the eons to be able to survive in the nutrient deprived, alkaline soils. The road conditions and characteristics range from flat and graded, to steep and off camber with reasonable amounts of exposure. Because of this, we believe a stock 4x4 (at a minimum) is the most suitable rig for taking on the New Idria Adventure Route in its entirety. It's hard to miss the remnants of Clear Creek's OHV pass, like closed off staging areas and moto tracks going every which way across the serpentine barrens. It's quite obvious that the area is still being used in an unofficial capacity by the OHV crowd. The loop through Clear Creek passes up and over San Benito Mountain (DP6). Standing at 5'240 feet, the the highest mountain in the Diablo Range. There are dozens, perhaps hundreds of mines and prospects within the San Benito mountains and Clear Creek Area, and the route passes through and nearby the since closed mining operations. As you make your way towards the old KCAC mine, you'll come across a number of signs indicating the area is closed, which is no longer the case since the area came under control of the Bureau of Land Management. Upon the ridge, the short scramble to the top of the rocks on Santa Rita Peak provide spectacular 360 degree views of the Diablo Range, Central Valley, and Sierra Nevada. Only a few short miles from Clear Creek's east gate, lies the old ghost town of New Idria. The road from the gate is steep, rocky, off camber, and numerous ditches that would prove difficult for a low clearance vehicle or high roof Sprinter van to cross. While New Idria is officially closed off to the public, you can still see dozens of old buildings, ruins, and giant smelting facility. A fire in 2010 destroyed or damaged many of the buildings at the north end of the ghost town. Keep in mind, there's a care taker that lives on site, who'll likely be on your tail should you decided to disregard the numerous Keep Out signs and chain link fence. From New Idria, the road turns into a pot hole strewn "paved" road. The road continues in its decrepit condition all the way to Griswold Hills. The rugged slopes and canyons of Griswold Canyon (DP12) look and feel more like the Southern California desert, than the western slope of Central California. The pavement returns to a wide dirt road on Panoche Road as you make your way to Tumey Hills. Depending on the time of year (Tumey Hills is closed to vehicles April 15 - October 15), the hills can be a brilliant green covered with grass, brown, or barren from overgrazing cattle. The place is spectacular if you're lucky enough to experience it before the grazing cattle strip the hills and canyons clean of grass. The Tumey, Griswold, and Panoche Hills form the foothills of the Diablo Range, and are an interesting transition zone between the more rugged San Benito Mountains and the great San Joaquin Valley. The final stretch of the route meanders through the rolling hills and pastureland along the dirt of Panoche Road, until reach the route's terminus near I-5. Camping Recommendations The sections along La Gloria Road and Old Hernandez Road are surrounded by private property, so dispersed camping is impossible without permission from a land owner. We recommend taking advantage of the various developed campgrounds in the Clear Creek Management Area. Dispersed camping is permitted throughout Tumey Hills.


Discovery Points

  • DP1 - La Gloria Road

  • DP2 - Old Hernandez Road

  • DP3 - San Benito River

  • DP4 - Clear Creek Canyon

  • DP5 - San Carlos Mine

  • DP6 - San Benito Mountains

  • DP7 - KCAC Mine

  • DP8 - Benitoite Gem Mine

  • DP9 - Santa Rita Peak Viewpoint

  • DP10 - Mexican Lake

  • DP11 - New Idria Mine and Ghost town

  • DP12 - Griswold Canyon

  • DP13 - Tumey Hills

 

Maps + Navigation


Gaia GPS Recommended Map Layers

  • Gaia base layer

Download Digital Mapping Files



 

Resources


Land Managers

Other Resources

  • n/a

 

Gallery



Terms of Use: Should you decide to travel a route that is published on Overlandtrailguides.com, you do so at your own risk. Always take the appropriate precautions when planning and traveling, including checking the current local weather, permit requirements, trail/road conditions, and land/road closures. While traveling, obey all public and private land use restrictions and rules, and carry the appropriate safety, recovery, and navigational equipment. The information found on this site is simply a planning resource to be used as a point of inspiration in conjunction with your own due-diligence. In spite of the fact that this route, associated GPS track (GPX and maps), and all route guidelines were prepared under diligent research by Overland Trail Guides, the route accuracy and current conditions of roads and trails cannot be guaranteed.



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4 Comments


Clear creek road is closed between west gate and east gate due to storm damage. Call and check before you go.

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La Gloria road from the east at hwy 25 says road closed. They are doing road work on it now.

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Coming from the north on old Hernandez Road, the road is closed at 5.5 miles, with a sign saying it’s private property. I wish I re-read your write up to ignore the signs… Grrr.

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I just motorbiked this whole route on March 17th 2023 (photos below). It took me about ~6hr and ~200mi of gas range, the 2~4 day estimate is definitely very conservative. Everything was passable on my Yamaha Tenere 700, didn't have to jump any logs. The old Clear Creek OHV area was ludicrously fun on the bike! Despite all the storms over the last few months all the roads were free and clear of big debris, there were only small rocks and one water crossing that was too high to fjord with my bike.


The San Benito River (DP3) was too high to cross on the Old Hernandez Trail at +36.486751, -121.020752 (4~5ft of fast-moving water) so I went around to…













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