Klamath River

The Klamath River (Karuk: Ishkêesh, Klamath: Koke, Yurok: Hehlkeek 'We-Roy is an American river that flows 263 miles (423 km) southwest through Oregon and northern California, cutting through the Cascade Range to empty into the Pacific Ocean. The river drains an extensive watershed of almost 16,000 square miles (41,000 km2) that stretches from the high desert country of the Great Basin to the temperate rainforest of the Pacific coast. The river is known for its basin's peculiar geography and has been called "a river upside down" by the National Geographic Society. The upper basin once contained vast freshwater marshes that provided habitat for thousands of migratory birds and other abundant wildlife; now most of it is developed, while the lower basin remains wild. It is the second largest river in California after the Sacramento River.

Since the Klamath is important for fish migration on the Pacific coast south of the Columbia River, its rainbow trout have adapted to unusually high water temperatures and acidity levels compared to other rivers in the Pacific Northwest. The numerous trout and other fish were a major source of food for Native Americans, who have been living in the basin for at least 7,000 years. A few decades after fur trappers for the Hudson's Bay Company arrived in the 1820s—the first whites to come to the basin, establishing the Siskiyou Trail along the Klamath and Trinity Rivers into the Sacramento Valley—the natives were forced into reservations.

During the latter days of the California Gold Rush, an increasing number of miners began working streams in the Klamath River region in search of gold. Steamboats operated briefly on the large lakes in the upper watershed before the establishment of agriculture in the 19th and 20th centuries. The growing industry in the upper basin led to the construction of many dams on the river, which have since caused water quality issues on the lower half. Some environmental groups have raised petitions against the construction of more dams and in support of removing the existing ones.

Because the Klamath includes many of the longest free-flowing stretches of river in California as well as some of its better whitewater runs, it has become a popular recreational river. Its watershed includes large swathes of the Klamath National Forest and Six Rivers National Forest. Although the lower Klamath remains undeveloped, massive diversions were once proposed to reroute the river into the Central Valley in order to supplement the region's water supply.