The Mad River (Wiyot: Baduwa't) is a river in upper Northern California. It flows for in a roughly northwest direction through Trinity County and then Humboldt County, draining a watershed into the Pacific Ocean north of the town of Arcata near [California Redwood Coast-Humboldt County Airport] in McKinleyville. The river's headwaters are in the Coast Range near South Kelsey Ridge. History Before Euro-American settlers arrived in the mid-1800s, the native peoples occupying the lower Mad River watershed were the Wiyot (from approximately Blue Lake to its mouth, plus the greater Humboldt Bay region) who spoke a dialect affiliated with the Algonquian language family, with upriver reaches controlled by three different groups whose languages are related to the Athabascan family, the Whilkut, Nongatl and Lassik (Baumhoff 1958). Today, among these distinct groups, only the Wiyot-affiliated Blue Lake Rancheria and the Wiyot Tribe of the Table Bluff Reservation are federally recognized tribes and the United States holds lands in trust for their citizens. The Whilkut, Nongatl and Lassik were essentially annihilated during the Bald Hills War in the 1860s. The river was named in December, 1849 in memory of an incident when Dr. Josiah Gregg lost his temper when his exploration party did not wait for him at the river mouth. Watershed and river modifications The Mad River drains approximately of the Coast Range Geomorphic Province and empties into the Pacific Ocean north of Humboldt Bay in Humboldt County, California. The basin is about in length and averages six miles (10 km) wide. Elevations range from sea level at the mouth to along the western ridge to in the headwaters. Principal tributaries to the Mad River include South Fork Mad River, North Fork Mad River, Barry Creek, Pilot Creek, Deer Creek, Bug Creek, Graham Creek, Grace Flat, Blue Slide Creek, Boulder Creek, Maple Creek, Canõn Creek, Lindsey Creek, and Mill (Hall) Creek. The river provides groundwater recharge for agricultural water supplies and is free-flowing for 85 percent of its length. Matthews Dam, about one third of the way down the river from its source, forms Ruth Reservoir. The dam is owned by Humboldt Bay Municipal Water District, which provides water from Ranney collectors near Essex for municipal and industrial use in Eureka, Arcata, Blue Lake and numerous unincorporated communities in the Humboldt Bay area. The reservoir can hold of water; and releases power a two megawatt hydro-electric plant generating 5 million kwh