The Thrap Mill and Pioneer Trails

Length 5.5 mi · Climbing 640 ft
California > Humboldt Redwoods and Vicinity > Benbow State Recreation Area

There are a few big redwoods on the flat after the Thrap Mill site


Benbow State Recreation Area has a single trail loop that was mainly built to give campers a place to go hiking. The well-built trail passes through some fairly scenic old-growth redwood uplands, eventually reaching a partially-logged flat where a redwood mill once stood. The trail is in excellent condition, and with the two notable exceptions described below, it’s completely clear of overgrowth and free of obstructions.

When the campground is open, the trail is surprisingly busy compared to the much more spectacular trails just a few minutes to the north. When the campground is closed, though, the trail is completely deserted.

If you’re not camping, it’s not possible to park anywhere near the trailhead; the closest place where you can park is in the day-use area across the river, which costs $6. You then have to ford the river and walk a half-mile to the trailhead. There’s also a pullout where you can park on Benbow Drive a few yards east of the campground entrance. It’s a slightly longer and less scenic walk to the trailhead, but it’s free and you don’t have to ford the river.

Starting from the day use area, head down toward the river and turn left. Cross under the freeway to reach a shallow spot where you can ford the river (it’s only about 3 inches deep at the end of summer, but there’s a lot of algae and the rocks are slippery), and continue along the gravelly beach on the other side until you see a path leading up the slope to your right. Take the path into the campground and turn right when you reach the paved road. Cross under the freeway again. In a few more yards you’ll see the trailhead directly in front of you.

A typical stretch of the Thrap Mill Trail

The trail starts off with a gentle climb up a pleasantly-wooded hillside, curving around the campground. There’s quite a bit of traffic noise from Highway 101, but it gradually fades away. At the intersection with the Pioneer Trail, stay to the left. The trail continues to climb the hillside, through increasingly redwood-filled woodland. The trail descends through an attractive grove of mid-sized upland redwoods. Just before the next intersection, there’s a 4-foot-diameter redwood across the trail that’s somewhat difficult to get around.

Turn left at the intersection. The trail descends through typically dry woodland that consists mainly of small trees dotted with a few decent-sized redwoods, and then abruptly enters a dark, logged forest. Below you is an alluvial flat that’s been mostly logged.

The Pioneer Trail passes a few mid-sized redwoods

The trail bottoms out and then reaches the mill site; there’s an interpretive sign and some old mill equipment. At this point the trail makes a left turn and runs along a low bluff above the river, folloing the route of an old dirt road. The trail has been completely washed away in two places, but it’s possible to cut through the redwood flat and pick up the trail again. Interestingly, about three-quarters of the flat has been clearcut, but near the end it abruptly changes to old-growth.

A half-dozen or so pretty good-sized redwoods grow along this part of the trail, right at the edge of the forest and above the river. These are the biggest redwoods of the hike. After passing these redwoods the trail, which used to be a road, climbs gently and then ends near the site of the dam. All that’s left of the dam are the cement footings. The recommended hike ends here, but you can continue to make your way along the river’s gravel banks.

The flat at the bottom of the trail



© 2010, 2017, 2019 David Baselt