Northeast of Fresno and Merced, the Dusy-Ershim OHV Route is the premier route in the Sierra National Forest. It traverses some of the most spectacular features of the forest as it winds through its 30-mile corridor between the Dinkey Creek and John Muir Wilderness areas. Its traditional trailhead begins at Courtright Reservoir and ventures three miles to Voyager Rock Campground. Thereafter, the trail deteriorates to a very difficult Class C that takes a minimum of two days to travel its entire length to Kaiser Pass Road, above Huntington Lake. The Mason Dixon line of the Dusy/Ershim route is the 50 degree-angle Chicken Rock and it has humbled many a driver with a vehicle lacking adequate horsepower.
To get there take Hwy 168 east of Clovis to the Dinkey Creek Road (just before you get to Shaver Lake). Follow the Dinkey Creek Road east to Dinkey Creek. At Dinkey Creek take the McKinley Grove Road toward Courtright Reservoir. At the Courtright Road, turn left and head north towards Courtright Reservoir. Cross the dam on the east side of the lake and stay on the road to the Dusy-Ershim OHV route sign.
The route begins at 8,400 feet elevation, with many open rocky areas. Be aware that portions of the trail cross large granite slabs and are marked with rocks. Elevation rises to 10,000 feet at Thompson Lake, remaining at the 9,000 to 10,000 feet for the rest of the route.
The first mile of the route is shared with foot and horse traffic. Please be considerate of other users and allow them safe passage.
Voyager Rock Campground has fire grates and tables, and is a popular camping area for fishing Courtright Reservoir. Leaving the campground, keep to the left as the "fun" begins at Chicken Rock, a definate attention getter. The panoramic view of the Le Conte Divide from the top is breath taking. The route wanders on to Dusy Creek where 4WD enthusiasts built the crossing over the creek.
Three hours ahead, is the very challenging stretch of road known as "Thompson Hill". Vehicles should have a body lift, running fairly cool and hitting on all cylinders. Even tires with aggressive tire tread will benefit with reduced air pressure. Even with all of this preparation, several stops may be necessary to throw a few rocks in the right places for traction. Access into Thompson Lake is closed at the wilderness boundary. A camping site with room for a few vehicles and tents is available here. The walk to the lake is short and easy.
The next stop available is East Lake, which is not visible from the route making it easy to miss. Its only a short walk to good fishing and an excellent photo spot with picturesque Dogtooth Peak in the background.
Ershim Lake is next with lots of space for camping and parking. Follow signs to campsites. The route from the top of Thompson Hill to Ershim Lake is fairly tame. However, the scenery becomes more interesting than the challenge of the route. This will soon change.
It will take about three hours to cover the four miles to Lakecamp Lake. Rainbow Trout make Lakecamp unique as the other lakes along this route have Brook Trout. Another fishing spot, Mallard Lake, is an easy 20 minute walk beyond Lakecamp.
The next four difficult miles to Whitebark Vista will test driving skills, but the panoramic views make it worth the effort. The route ends at Whitebark Vista. Many people prefer use this White Bark Vista as a starting point. Huntington Lake is 30 minutes away.
Note: As of September 2007, ATV riding is only permitted on Forest Service roads with vertical number signs. In addition, the ATV must have a valid California green ATV sticker.
Overall, Dusy/Ershim OHV Route is the 41st most popular ATV riding trail of all 106 ATV trails in California.