From Highway 33, travel east on Rose Valley Road to Piedra Blanca Trailhead. Starting from the parking lot at Piedra Blanca, the trail quickly drop down to the river crossing, after the crossing Lion Creek and Sespe Creek is the Gene Marshall Piedra Blanca trail junction. The Sespe River Trial proceeds down stream and is in excellent shape. At one point the trail was a forest service road that lead to Willets Hot Spring, after the wilderness protection act the road was closed to car traffic and only open for hiking and horseback riding.
Continue hiking 4.3 miles from the trial head to the first camp along the trail named Bear Creek Camp (2820 feet). This is a wonderful camp located on a large sandbar with a swimming and shade from cottonwood trees. Past the camp you will come to Kerr Spring, the first year-round water source, which is located .8 miles further from Bear Creek Camp on the south side of the river. Continuing towards Hot Springs Canyon, there are several more camps before you reach Willets. First is Oak Flat Camp (2600 feet) (7.4 miles from trailhead). After Oak Flat Camp the trail has another junction with the Red Reef Trail (21W08). Another 9.4 miles down the trail is Thacher Camp (2528 feet) which is sort of an overflow camp for Willet Camp and Hot Spring (2520 feet) (9.8 miles), as you continue on you will find Hartman Camp (2489 feet) (10.9 miles), and then Coltrell Flat Camp (2312 feet) (14 miles). Just after Coltrell Flat the third trail juntion is with the Johnston Ridge Trail (20W12). The Johnston Ridge Trail leads to Mutau Flat and the Matau Trail. Past the junction you will find Shady Camp (2440 feet) at 17.5 miles. The trail then quickly ends near Alder Creek Camp (2520 feet) and turns into the Alder Creek Trail.
The entire length of the Sespe River Trail has ten crossings of the Sespe River. Use caution when travelling during the wet season due to the potential of flash flooding. Since this trail is in the wilderness, only hikers and equestrians are permitted. The river is considered one of the best trout fishing streams in Ventura County. It used to have an annual Steethead Trout run but dam construction and drought years have ended these runs.
Sespe Creek is a stream, some 61 miles long in Ventura County. The creek starts at Potrero Seco in the eastern Sierra Madre Mountains, and is formed by more than thirty tributary streams of the Sierra Madre and Topatopa Mountains, before it empties into the Santa Clara River in Fillmore. Thirty-one miles (50 km) of Sespe Creek is designated as a National Wild and Scenic River and National Scenic Waterway, and is untouched by dams or concrete channels. It is one of the last wild rivers in Southern California. It is primarily within the southern Los Padres National Forest.
The name Sespe can be traced to a Chumash Indian village, called Cepsey, Sek-pe or S'eqpe' ("Kneecap") in the Chumash language in 1791. The village appeared in a Mexican Alta California land grant called Rancho Sespe or Rancho San Cayetano in 1833
The creek remains free from major habitat modifications and is noteworty for its lack of dams, although one was originally proposed for a site named Topa Topa near Sespe Hot Springs in the Sespe Wilderness. After originating above 5,000 feet (1,500 m) in the Sierra Madre Mountains in the northwest corner of the Ojai Ranger District, about 75 percent of the Sespe Creek subwatershed is characterized by numerous rugged slopes and canyon walls of the southern Pine Mountains. It flows intermittently but is characterized by a series of permanent deep pools. Major tributaries include the Lion Canyon, Hot Springs Canyon, Timber, West Fork Sespe and Little Sespe Creeks, although over 30 creeks and springs nourish it. Sespe Creek receives most of its rainfall between January and April, and furnishes 40% of the water flowing in the Santa Clara River.
Also known as Arroyo Sespe, Cespai River, Sespe River.