The Eel River represents California's third largest watershed. The mainstem flows more than two hundred air miles and travels over 800 river miles from the headwaters above Lake Pillsbury in Lake County to the ocean. The Eel River has received both state (1972) and federal (1981) wild and scenic river designation, which protects the river from dams and ensure that environmental concerns rank equally with development and industry.
The three forks of the Eel illustrate several river types, originating in high mountain pine forests; flowing through steep canyons and coastal redwood forests; and emptying into the Pacific in a gently sloping valley with virgin redwood stands. The North Fork flows 35 miles, completely in Trinity County. The Middle Fork, the Eel's largest tributary, travels a total of 70 miles before joining the mainstem Eel. The South Fork begins in Mendocino County and travels through ancient redwood forests to join the mainstem. A fourth tributary, the Van Duzen River enters the mainstem of the Eel once it has reached the coastal plain.
January 19, 1981. From the mouth of the river to 100 yards below Van Ardsdale Dam. The Middle Fork from its confluence with the main stem to the southern boundary of the Yolla Bolly Wilderness Area. The South Fork from its confluence with the main stem to the Section Four Creek confluence. The North Fork from its confluence with the main stem to Old Gilman Ranch. The Van Duzen River from the confluence with the Eel River to Dinsmure Bridge.
The Eel River is a premium fishery for coho salmon, chinook salmon, and steelhead and is rated as being an important fishery for American Shad. In normal years, chinook begin arriving in August and remain until rains allow them upstream. The run continues through December, with the peak in late October.
Dos Rios, located at the confluence of the Middle Fork of the Eel River and the mainstem, is the put-in for a popular four-day trip through the Eel River Canyon to Alderpoint. The river offers several enjoyable one-day runs, ranging from Class I to Class III, and opportunities for a wide range of paddle craft. A number of trails access the river, and the highest public use is by summer swimmers downstream near the Eel River Work Center and Eel River Campground.