The proposed Underwood Wilderness encompasses the northern end of the South Fork Trinity River, including the 8-mile remote and botanically special South Fork Trail. Hell’s Half Acre is host to a variety of plants.
Take South Fork Road (County Road 447) from the confluence with the Trinity River on Highway 299 near the borders of Trinity and Humboldt County. Follow the road south for 9.2 miles, or approximately 45 minutes to one hour. Swimming can be found at Broken Bridge and Surprise Creek.