The Sacramento River is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for 400 miles (640 km) before reaching the Sacramento–San Joaquin River Delta and San Francisco Bay. The river drains about 26,500 square miles (69,000 km2) in 19 California counties, mostly within the fertile agricultural region bounded by the Coast Ranges and Sierra Nevada known as the Sacramento Valley, but also extending as far as the volcanic plateaus of Northeastern California. Historically, its watershed has reached as far north as south-central Oregon where the now, primarily, endorheic (closed) Goose Lake rarely experiences southerly outflow into the Pit River, the most northerly tributary of the Sacramento.
The Santa Ana River is the largest river entirely within Southern California in the United States. It rises in the San Bernardino Mountains and flows for most of its length through San Bernardino and Riverside counties, before cutting through the northern Santa Ana Mountains via Santa Ana Canyon and flowing southwest through urban Orange County to drain into the Pacific Ocean. The Santa Ana River is 96 miles (154 km) long, and its drainage basin is 2,650 square miles (6,900 km2) in size.
The Trinity River 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 Eel River is a major river, about 196 miles (315 km) long, of northwestern California. The river and its tributaries form the third largest watershed entirely in California, draining a rugged area of 3,684 square miles (9,540 km2) in five counties. The river flows generally northward through the Coast Ranges west of the Sacramento Valley, emptying into the Pacific Ocean about 10 miles (16 km) downstream from Fortuna and just south of Humboldt Bay. The river provides groundwater recharge, recreation, and industrial, agricultural and municipal water supply.
Coyote Creek is a river that flows through the Santa Clara Valley in Northern California. Its source is on Mount Sizer, in the mountains east of Morgan Hill. It eventually flows into Anderson Lake in Morgan Hill and then northwards through Coyote Valley to San Jose, where it empties into San Francisco Bay.
Malibu Creek is a year-round stream in western Los Angeles County, California. It drains the southern Conejo Valley and Simi Hills, flowing south through the Santa Monica Mountains, and enters Santa Monica Bay in Malibu, California. The Malibu Creek watershed drains 109 square miles (280 km2) and its tributary creeks reach as high as 3,000 feet (910 m) into Ventura County, California. The creek's mainstem begins south of Westlake Village at the confluence of Triunfo Creek and Lobo Canyon Creek, and flows 13.4 miles (21.6 km) to Malibu Lagoon.
The Ventura River, in western Ventura County in southern California, United States, flows 16.2 miles (26.1 km) from its headwaters to the Pacific Ocean. The smallest of the three major rivers in Ventura County, it flows through the steeply sloped, narrow Ventura Valley, with its final 0.7 miles (1.1 km) through the broader Ventura River estuary, which extends from where it crosses under a 101 Freeway bridge through to the Pacific Ocean.
Alameda Creek is a large perennial stream in the San Francisco Bay Area. The creek runs for 45 miles (72 km) from a lake northeast of Packard Ridge to the eastern shore of San Francisco Bay by way of Niles Canyon and a flood control channel. Along its course, Alameda Creek provides wildlife habitat, water supply, a conduit for flood waters, opportunities for recreation, and a host of aesthetic and environmental values. The creek and three major reservoirs in the watershed are used as water supply by the San Francisco Public Utilities Commission, Alameda County Water District and Zone 7 Water Agency. Within the watershed can be found some of the highest peaks and tallest waterfall in the East Bay, over a dozen regional parks, and notable natural landmarks such as the cascades at Little Yosemite and the wildflower-strewn grasslands and oak savannahs of the Sunol Regional Wilderness. After an absence of half a century, ocean-run steelhead trout are able to return to Alameda Creek to mingle with remnant rainbow trout populations. Completion of a series of dam removal and fish passage projects, along with improved stream flows for cold-water fish and planned habitat restoration, enable steelhead trout and Chinook salmon to access up to 20 miles (32 km) of spawning and rearing habitat in Alameda Creek and its tributaries. The first juvenile trout migrating downstream from the upper watershed through lower Alameda Creek toward San Francisco Bay was detected and documented in April 2023.
Sonoma Creek is a 33.4-mile-long (53.8 km) stream in northern California. It is one of two principal drainages of southern Sonoma County, California, with headwaters rising in the rugged hills of Sugarloaf Ridge State Park and discharging to San Pablo Bay, the northern arm of San Francisco Bay. The watershed drained by Sonoma Creek is roughly equivalent to the wine region of Sonoma Valley, an area of about 170 square miles (440 km2). The State of California has designated the Sonoma Creek watershed as a “Critical Coastal Water Resource”. To the east of this generally rectangular watershed is the Napa River watershed, and to the west are the Petaluma River and Tolay Creek watersheds.
San Juan Creek, also called the San Juan River, is a 29-mile (47 km) long stream in Orange and Riverside Counties, draining a watershed of 133.9 square miles (347 km2). Its mainstem begins in the southern Santa Ana Mountains in the Cleveland National Forest. It winds west and south through San Juan Canyon, and is joined by Arroyo Trabuco as it passes through San Juan Capistrano. It flows into the Pacific Ocean at Doheny State Beach. San Juan Canyon provides a major part of the route for California State Route 74.
Alhambra Creek is a stream in Contra Costa County, in the East Bay region of the San Francisco Bay Area in northern California.
The American River is a 30-mile (50 km)-long river in California that runs from the Sierra Nevada mountain range to its confluence with the Sacramento River in downtown Sacramento. Via the Sacramento River, it is part of the San Francisco Bay watershed. This river is fed by the melting snowpack of the Sierra Nevada and its many headwaters and tributaries, including the North Fork American River, the Middle Fork American River, and the South Fork American River.
Adobe Creek, historically San Antonio Creek, is a 14.2-mile-long (22.9 km) northward-flowing stream originating on Black Mountain in the Santa Cruz Mountains. It courses through the cities of Los Altos Hills, Los Altos, and Palo Alto on its way to the Palo Alto Flood Basin and thence to southwestern San Francisco Bay in Santa Clara County, California, United States. Historically, Adobe Creek was a perennial stream and hosted runs of steelhead trout entering from the Bay, but these salmonids are now blocked by numerous flood control structures, including a tidal gate at the creek's mouth and a long concretized rectangular channel culminating in an impassable drop structure at El Camino Real. The co-founders of Adobe Systems both lived on Adobe Creek.
Stony Creek is a 73.5-mile (118.3 km)-long tributary of the Sacramento River in Northern California. It drains a watershed of more than 700 square miles (1,800 km2) on the west side of the Sacramento Valley in Glenn, Colusa, Lake and Tehama Counties.
The Middle Fork American River is one of three forks that form the American River in Northern California. It drains a large watershed in the high Sierra Nevada west of Lake Tahoe and northeast of Sacramento in Placer and El Dorado Counties, between the watersheds of the North Fork American River and South Fork American River. The Middle Fork joins with the North Fork near Auburn and they continue downstream to Folsom Lake as the North Fork, even though the Middle Fork carries a larger volume of water.
Keswick Dam is a concrete gravity dam on the Sacramento River about 2 miles (3.2 km) northwest of Redding, California. Part of the U.S. Bureau of Reclamation's Central Valley Project, the dam is 157 feet (48 m) high and impounds the Keswick Reservoir, which has a capacity of 23,800 acre⋅ft (29,400,000 m3). The dam's power plant has three turbines with a generating capacity of 117 megawatts (MW), which, in 1992, was uprated from its original 75 MW. The dam and reservoir serve as an afterbay to regulate peaking power releases from the Shasta Dam upstream.
Pacheco Creek is a 28 miles (45 km) west by southwest flowing stream which heads in the Diablo Range in southeastern Santa Clara County and flows to San Felipe Lake, the beginning of the Pajaro River mainstem, in San Benito County, California.
Cottonwood Creek is a major stream and tributary of the Sacramento River in Northern California. About 68 miles (109 km) long measured to its uppermost tributaries, the creek drains a large rural area bounded by the crest of the Coast Ranges, traversing the northwestern Sacramento Valley before emptying into the Sacramento River near the town of Cottonwood. For its entire length, it defines the boundary of Shasta and Tehama counties. Because Cottonwood Creek is the largest undammed tributary of the Sacramento River, it is known for its Chinook salmon and steelhead runs.
Cow Creek is a tributary of the Sacramento River in Shasta County, California. About 46.9 miles (75.5 km) long measured to its longest source, it drains a hilly, rural region at the northern end of the Sacramento Valley east of Redding. The creek begins at Millville at the confluence of Old Cow and South Cow Creek and flows west to Junction, where it turns south, joining the Sacramento near Anderson. Despite its name, Cow Creek is closer in size to a river, especially in winter when it is prone to large flash floods, accounting for up to 21 percent of the Sacramento's peak flows at Red Bluff.
Thomes Creek is a major watercourse on the west side of the Sacramento Valley in Northern California. The creek originates in the Coast Ranges and flows east for about 62 miles (100 km) to join the Sacramento River, at a point about 7 miles (11 km) northeast of Corning in Tehama County.
