Twain Harte to Lyons Dam Loop, Sugar Pine Rail Trail: Twain Harte to Lyons Dam

I’m posting two loops for this bike ride–one for a 15-mile loop out of Twain Harte that connects Forest Route 4N02 on the north side of the South Fork Stanislaus to a five-mile segment of the Sugar Pine Rail Trail on the south side, and another for ten-mile out-and-back on the rail trail that is a great casual/kids ride. First, the longer loop. Also see Pinecrest to Columbia for more on the Sugar Pine Rail Trail along the South Fork Stanislaus River.

Twain Harte to Lyons Dam Loop

I started the longer loop at Eprosen Park in Twain Harte. You could just as easily park at the start of the rail trail on Confidence South Fork Road in order to cut out some climbing and travel on surface streets, but there are restrooms and far better parking at the park. From Eprosen Park find Joaquin Gully, climb up to Middle Camp Road, and turn right. At 1.3 miles (from start of ride), look for South Fork Road branching off to the left. I don’t have any preference for direction on this ride; I’ll present it going clockwise.

Turn left at South Fork Road and proceed to the South Fork Stanislaus taking note of the ditch crossing and the change to gravel. There are ditch segments suitable for riding, but this one turns to a flume not far upstream–great for hiking and fishing, not for bikes.

PG&E Main Canal at South Fork Road

South Fork Stanislaus River

Immediately after the South Fork bridge there are two roads branching off to the right. One is a private driveway along the river, and the other is a paved road heading uphill with a sign for “Heavenly Hills”. Take the road to Heavenly Hills. After a climb, the road levels out and branches. First there are driveways to the left, then Heavenly Hills down to the right; pass both and keep going uphill onto Forest Route 4N02.

Forest Route 4N02 at Heavenly Hills

There are numerous private cabins along the road and private property/no trespassing signs. Respect private property by staying on the road. 4N02 gets a bit chunky with loose rock, but not for too long. Eventually the road branches in three directions: left has a marker for 3N35, straight is unmarked but is 4N02 which proceeds along the north shore of Lyons Reservoir, right is unmarked and goes over a small hill before descending to Lyons Dam. Take the road to the right to cross the dam to the Sugar Pine Railroad grade.

Fork in 4N02 north of Lyons Dam

Crossing the dam has some issues which may prevent some from doing this loop. First, the descent to the dam is a rather gnarly but short scramble down a rocky eroded hill. I just walk it down to avoid needing services at the second impediment–the helicopter landing pad at the north end of the dam. I’ve never seen a helicopter there, but it’s possible that access could be blocked.

Descent to dam and helicopter pad on north side of Lyons Dam

Be prepared to lift your bike

Third, the path along the dam is blocked by the controls for the dam gates. You need to be able to lift your bike above the railing to get by. Fisherpersons like to hang out by these control boxes because they provide a flat surface for their stuff. Don’t be shy about coming through–it happens all day long, I’m sure. Be polite and thankful.

At the top of the stairway from the dam, go right to return to Twain Harte on the railroad grade, or left to check out the facilities. There is a pit toilet, garbage can, and a parking area at Lyons and not much else. Water contact is prohibited, so it’s pretty much fishing, picnicking, hiking, and biking. If you want to pollute the water with your body, you’ll have to do it in the river upstream of the lake. The lake is under PG&E jurisdiction but is open to the public for day use. The rail trail also continues to the east along the river.

Lyons Dam

The rail trail back to Twain Harte is wide and flat and easy. Expect springtime mud and summer/fall dust. At the Lyons end, the trail starts down in the river canyon and the vegetation is lush on the north side of the canyon. Look for dogwood and big leaf maple for springtime flowering and fall color. As the river canyon descends towards Twain Harte, the trail is more open and exposed. Look for views across the canyon to the north.

Through cut on Sugar Pine RR Grade

There are some logged areas along the trail. Most of the trail is on land owned by Sierra Pacific Industries, and public access is allowed by SPI. Though the stumpy hillsides aren’t so pretty, keep in mind that the railroad was built for logging. Please stay on the trail and respect private property.

To complete the loop, turn left on exiting the rail trail onto Confidence South Fork Road and then turn right onto Middle Camp Sugar Pine Road. Take Middle Camp Sugar Pine back to Joaquin Gully and backtrack to Eprosen Park.

Twain Harte to Lyons Dam Out-and-Back on the Sugar Pine Rail Trail

The railroad grade itself (see above) makes a fine ten-mile out-and-back for families or casual riders. Don’t look for helpful signage at either end of the trail–there is none. For a formal parking area and restroom, start at Lyons Reservoir. Access is via Lyons Reservoir Road off of SR 108 in Sierra Village. Follow the road from the parking area to the dam; the road turns into the trail as it continues past the dam.

From Twain Harte, look for the start of the trail on the east side of Confidence South Fork Road just north of the intersection with Middle Camp Sugar Pine Road. There are a few parking spots scattered along the edge of Confidence South Fork Road and additional parking on the shoulder of Middle Camp in front of the  substation just west of Confidence South Fork. Look for the following sign and gate. Welcome! This is it!

Twain Harte entrance to Sugar Pine Rail Trail

Download file to view the ride on the Google Earth bike map
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Get help with using Google Earth to view the map file
Download the .gpx file for the loop if you want to upload it to a GPS

  • Downside—Some rough road on 4N02 and access issues at the dam will make the longer loop too much for some riders, limited parking and signage at the Twain Harte end of the rail trail.
  • Upside—Short quick rides out of Twain Harte, RR grade alone is a great trip for kids with lake and dam to explore, elevation takes the temperature down a notch in summer heat.
  • Bring a good (better than Google) paper map of Stanislaus Forest Roads. See the page of Stanislaus Forest tips. Ride is in the Twain Harte quad.
  • Loop 15 miles; about 2,400 feet total climb. RR grade out-and-back 10 miles maybe 300 feet total climb. (Google says 750, but I don’t believe it.)
  • roads: paved, gravel, mostly dirt.
  • terrain: moderate to steep on 4N02 and surface streets, very mild on RR grade.
  • tires: cross to mountain, most will prefer mountain.
  • seasons: Winter closure gates on 4N02 and Lyons Reservoir Road.
  • current weather
This entry was posted in casual and kids, mid elevation, mixed and tagged , , , , , . Bookmark the permalink.

One Response to Twain Harte to Lyons Dam Loop, Sugar Pine Rail Trail: Twain Harte to Lyons Dam

  1. Anonymous says:

    This was very helpful!! Did this loop today and your pictures helped. Thank you!!

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