The Middle Fork Eel River flows almost 70 stream miles. It rises in the Yolla Bolly-Middle Eel Wilderness at the crest of the Coast Range about a mile or so north of Wrights Ridge and west of The Knob, at the confluence of several small unnamed streams. It makes a large bend to the south, then southeast past the confluence with Rattlesnake Creek and the boundary between Trinity and Mendocino Counties. Turning south around Taliaferro Ridge at the Beaver Creek confluence, it then runs southwest to where the Black Butte River enters from the left. Williams Creek enters on the right, then the Middle Fork flows south through Round Valley Indian Reservation, passing within a few miles of Covelo before receiving Mill Creek from the right. Hayshed and Elk Creeks both enter from the left as the river rounds a bend to the north. Afterwards, the river's final miles are spent flowing westwards through a gorge to the confluence with the main stem near Dos Rios.
Dam proposal
In 1967, the U.S. Army Corps of Engineers proposed to build an enormous dam just above the confluence of the Eel River and the Middle Fork Eel River at Dos Rios. The Dos Rios Dam would have been tall, creating a reservoir that covered of land. If built, this dam would have diverted most of the flow of the river into the Central Valley for irrigation purposes. The project was defeated by outcry from local residents and the intervention of then-California governor Ronald Reagan. Reagan remarked, "Enough treaties had already been broken with the Indians".
Ecology
The river provides wildlife habitat for preservation of rare and endangered species including cold freshwater habitat for fish migration and spawning. In a 1965 California Fish and Wildlife Plan, the Middle Fork Eel River watershed supported an annual run of 23,000 Steelhead trout in 178 miles of stream habitat. Steelhead surveys were conducted by DFG and USFS from 1966 to 1999. In 1999 they described the Middle Fork summer steelhead run as “The largest remaining wild run of these magnificent fish”. It was noted to be “...probably the only population that has not been touched by a hatchery program, and as such, is most likely the State’s most important summer steelhead population”. Counts from the annual surveys indicated that the Middle Fork summer steelhead population has declined since 1987, to a count of 471 fish in 1999.
