Trinity River (California)

Trinity River
Hoopa River
Trinity River near Weaverville
Country	United States
State	California
Tributaries
- left	East Fork Trinity River, South Fork Trinity River
- right	Stuart Fork Trinity River, North Fork Trinity River, New River
Source	Scott Mountains
- elevation	5,557 ft (1,694 m)
- coordinates	41°19′53″N 122°33′9″W / 41.33139°N 122.55250°W / 41.33139; -122.55250
Mouth	Klamath River
- location	Weitchpec
- elevation	190 ft (58 m)
- coordinates	41°11′5″N 123°42′31″W / 41.18472°N 123.70861°W / 41.18472; -123.70861Coordinates: 41°11′5″N 123°42′31″W / 41.18472°N 123.70861°W / 41.18472; -123.70861
Length	165 mi (266 km)
Basin	2,936 sq mi (7,604 km2)
Discharge	for Hoopa
- average	5,230 cu ft/s (148 m3/s)
- max	231,000 cu ft/s (6,541 m3/s)
- min	162 cu ft/s (5 m3/s)
Map of the Trinity River and Klamath River watersheds. The Trinity River is shown in dark blue, with its watershed highlighted in dark yellow. The South Fork Trinity River extends southward, while the main Trinity River curves east then north.

The Trinity River (originally called the Hoopa or Hupa by the Yurok, and hun' by the Natinixwe/Hupa people) is a major river in northwestern California in the United States, and is the principal tributary of the Klamath River. The Trinity flows for 165 miles (266 km) through the Klamath Mountains and Coast Ranges, with a watershed area of nearly 3,000 square miles (7,800 km²) in Trinity and Humboldt Counties. Designated a National Wild and Scenic River, along most of its course the Trinity flows swiftly through tight canyons and mountain meadows.

The river is known for its once prolific runs of anadromous fish, notably Chinook salmon and steelhead, which sustained Native American tribes for thousands of years. Due to its remoteness, the Trinity did not feature prominently in the early European colonization of California, but the gold rush in the mid-1800s brought thousands of gold seekers to the area. The river was named by Major Pierson B. Reading who, upon reaching the river in 1848, mistakenly believed it to flow into the Pacific Ocean at Trinidad Bay. During and after the gold rush, the influx of settlers and miners into the Trinity River country led to conflict with indigenous tribes, many of which saw severe depopulation due to fighting and foreign diseases. In the following decades logging and ranching, combined with mining runoff, significantly changed the river's ecology and led to the decline of its fish populations.