Mad River (Vi’ot: Baduva’t ) is a river in northern California. It flows for 113 miles (182 km) in a roughly northwest direction through Trinity County, and then Humboldt County, draining a watershed of 497 square miles (1,290 km2) into the Pacific Ocean north of the city of Arcata near [California Redwood Coast Airport, Humboldt County ] in McKinleyville. The source of the river is in a coastal range near South Kelso Ridge.
The river provides recreational opportunities and is an important habitat for fish and wildlife. The flora of this area includes the Mad River hawksbeard (Erigeron maniopotamicus), a wildflower named after the river [8]. Key fish species include coho salmon (Oncorhynchus kisutch), Chinook salmon (O. tshawytscha), and steelhead (O. mykiss), which were federally listed as threatened in the Mad River in 1997, 1999, and 2000. Two endangered species of smelt – the longfin smelt (Spirinchus thaleichthys) and eulachon (Thaleichthys pacificus) – are also listed as present in the estuarine part of the Mad River, but have not been observed in recent years.
Before entering the ocean, the river sharply turns north near the triple junction of the Gorda Plate, North American Plate, and Pacific Plate.
