Hayfork Creek

Hayfork Creek
Hayfork River, Hayfork Branch, Hayfield Fork Trinity River
Name origin: Named for Hayfork, California which in turn got its name from being the richest agricultural region of Trinity County
Country	United States
State	California
Tributaries
- left	Salt Creek (Orange County), Tule Creek
- right	East Fork Hayfork Creek, Carr Creek, Big Creek (San Joaquin River), Corral Creek
Cities	Hayfork, Hyampom
Source	Brushy Mountain (Shasta County, California)
- location	Shasta-Trinity National Forest
- elevation	5,052 ft (1,540 m)
- coordinates	40°17′36″N 123°04′22″W / 40.29333°N 123.07278°W / 40.29333; -123.07278
Mouth	South Fork Trinity River
- location	Hyampom
- elevation	1,276 ft (389 m)
- coordinates	40°36′51″N 123°27′06″W / 40.61417°N 123.45167°W / 40.61417; -123.45167Coordinates: 40°36′51″N 123°27′06″W / 40.61417°N 123.45167°W / 40.61417; -123.45167
Length	50 mi (80 km), north then west
Basin	379 sq mi (982 km2)
Discharge
- average	552 cu ft/s (16 m3/s)
- max	29,400 cu ft/s (833 m3/s)
- min	19 cu ft/s (1 m3/s)
Map of the South Fork Trinity River basin, showing Hayfork Creek to the right of the main stem.

Hayfork Creek is a tributary of the South Fork Trinity River in Northern California in the United States. At over 50 miles (80 km) long, it is the river's longest tributary and is one of the southernmost streams in the Klamath Basin. It winds through a generally steep and narrow course north then west through the forested Klamath Mountains, but also passes through the Hayfork and Hyampom Valleys, which comprise the primary agricultural regions of Trinity County.

The watershed of the creek was originally inhabited by the Wintu people. Human habitation in the basin goes back for more than 5,000 years. The first Euro-Americans arrived in the late 1820s, but the basin was not developed until the 1850s with the onset of the California Gold Rush. The fertile soils and mild climate of the river valley led to it becoming the most prosperous agricultural area of the county. Logging began in the 1920s, and by the 1940s started to have an adverse impact on the ecology of the watershed, which includes once-abundant populations of Coho salmon and steelhead trout.

The Hayfork rises on the west flank of Brushy Mountain some 7 miles (11 km) south of the hamlet of Wildwood. Flowing generally north through a deep forested valley in the Shasta-Trinity National Forest, it receives the East Fork from the right. Five miles (8 km) downstream, it enters the Hayfork Valley, a large agricultural basin in the middle of the Klamath Mountains. Here it receives Summit and Big Creeks from the right, while Salt Creek enters from the left. The stream also passes State Route 3 and the small town of Hayfork.