Humboldt Redwoods State Park in general is a fantastic location for trail running objectives. The park encompasses over 53,000 acres, and 17,000 acres of those acres are pristine old growth redwood forest. There are over 100 miles of trails to explore passing through various habitats. For flatter trail runs, the Bull Creek Trail (both south and north), Big Tree Trail, Homestead Trail and the River Trail are great options. You can literally run near the banks of Bull Creek or the South Fork of the Eel River for dozens of miles, all under old growth redwoods. Note that accessibility to the River Trail and South Bull Creek Trail is very limited in the winter and spring months when seasonal bridges across Bull Creek are removed. For some vertical, the Peavine Ridge-Thornton-Look Prairie Loop is a great option with varied terrain and foliage as the forest shifts from redwood to primarily douglas fir woodland. The Johnson Camp Trail and Grasshopper Trail provide access to the summit of 3,379 foot Grasshopper Peak with panoramic views of the Humboldt basin. As to be expected, the redwoods are primarily in the lower lying areas near the rivers and streams so any trails with substantial ascent will transition to a non-redwood forest. I look forward to returning to Humboldt Redwoods and exploring more of its awesome trails.