Trip report
Apr 23, 2026 — Mount Saint Helena is part of the Mayacamas Mountains, a subrange of the California Coast Ranges. While the views are expansive, it’s unfortunately almost the entire hike follows a service road to communication towers. The hike begins within Robert Louis Stevenson State Park, the popular trailhead that’s just a parking lot along CA-29. More hikers seem to be interested in the Table Rock Trail.
The lower section follows the Stevenson Memorial Trail, a short set of switchbacks that passes historical markers tied to the novelist Robert Louis Stevenson. It’s a good warm-up through the forest, but misleading since it’s the only portion of the hike that is on an actual trail. From there, the trail exits onto a wide service road that continues the long, consistent ascent toward the summit ridge.
As the trees thin out, the hike opens into exposed chaparral. The views expand across Napa, Sonoma, and Lake counties. There are a couple of road switchbacks that can be cut via a social trail. The summit reward for this extensive road walk is a broad, open summit with panoramic views in every direction. It’s a bummer so many beautiful peaks in the Bay Area are overrun by roads rather than trails.