Cool off Streamside This Summer: Ten Uniquely California Rivers

What makes the best summer vacations? Rivers. Swimming, fishing, napping on a shady riverbank—there’s no better summer getaway. Fortunately, dozens of jaw-droppingly beautiful rivers run through the Golden State.

But which are the most uniquely Californian? Those that have the highest number of freshwater plants and animals, found nowhere else on Earth but here. From our Santa Ana three-spine stickleback to the California fairy shrimp, California’s rivers are home to a wildly diverse collection of native plants, insects and fish unique to our state.

In fact, with our mind-boggling variety of landscapes from deserts to redwoods to beaches, California has more endemics—species naturally occurring in one specific region only—than any other state in the U.S.

Just in time for summer, The Nature Conservancy’s scientists undertook an analysis to identify those California rivers with the greatest number of endemics. The great news is that these same rivers are also some of our most spectacular vacation destinations.

So if you’re looking for the most quintessentially California rivers to explore this summer, you can’t do any better than these. Grab your water gear and get out there and enjoy!

Tuolumne River
Lower Sacramento River
Santa Ana River
Cache Creek/Clear Lake
Lower Pit River
Lost River
Owens River
San Francisco Bay Southern Streams
Upper Klamath River
Amargosa River

TUOLUMNE RIVER—Stanislaus, Tuolumne and Mariposa Counties
Designated a National Wild and Scenic River, the majestic Tuolumne begins at 13,000 feet in Yosemite National Park, winding through picture-perfect Tuolumne Meadows and providing world-class recreational opportunities from fishing to hiking for people of all ages and abilities.

What to look for:
Yosemite toad (Anaxyrus canorus)
Active only during the summer months, the Yosemite toad has only a few months to reproduce and eat enough to survive the long hibernation under the snow.

Dwarf downingia (Downingia pusilla)
Look for this tiny white or blue bellflower near the water’s edge.

Number of endemic species: 34

LOWER SACRAMENTO RIVER—Yolo, Sacramento and Solano Counties
Some say it’s the best fishing in the state; some say it’s the incomparable birding; while others vocally defend it as having the very best picnic spots. Winding its way south from Redding, the Lower Sacramento River winds through gentle river terraces, sheer canyon walls and rolling oak woodlands, providing something for everyone.

What to look for:
Central Valley spring Chinook salmon (Oncorhynchus tshawytscha)
In this southernmost habitat for Chinook, adults migrate upstream in spring; spend hot summer months in deep, cold pools; and spawn in early fall. Offspring head to sea after a few months in fresh water.

Valley arrowhead (Sagittaria sanfordii)
Keep an eye out for this beautiful water plant with arrowhead-shaped leaves and spectacular white summer flowers on two- to four-foot stalks.

Number of endemic species: 33

SANTA ANA RIVER—San Bernardino, Riverside, Los Angeles and Orange Counties
Southern California’s largest river, the Santa Ana flows through incredibly diverse terrain from alpine mountain peaks to arid plains and deserts. Bordering the river for more than 70 miles is the Santa Ana River Bicycle Trail that when finished will run through three counties, 17 cities and two national forests.

What to look for:
California treefrog (Pseudacris cadaverina)
With an effective camouflage, these frogs are easily overlooked as granite rocks. In the evening, listen for their distinct duck-like call.

Arroyo chub (Gila orcuttii)
This small fish is adapted to surviving the warm, fluctuating streams of the Los Angeles Plain, which historically shifted naturally between muddy torrents in the winter and clear brooks in the summer.

Number of endemic species: 24

Cache Creek flows into Clear Lake with more than 100 miles of shoreline and geothermal hot springs, making it a haven for outdoor recreation. Grab a paddle or a rod—boating, paddle sports and fishing are some of the most popular activities on the lake.

What to look for:
Clear Lake hitch (Lavinia exilicauda chi)
The hitch spawning is as spectacular as any salmon run on the Pacific coast, with hitches by the thousands ascending the many streams leading into Clear Lake during spring.

Many-flowered navarretia (Navarretia leucocephala plieantha)
Also known as the whitehead pincushion plant, the flowers of this member of the phlox family vary from white to blue.

Number of endemic species: 30

Described as the finest naturally occurring wild trout fishery in California, this renowned fly-fishing destination has a wealth of pools, pockets, runs and riffles. Located in the northeast corner of the state, the Lower Pit flows into Shasta Lake.

What to look for:
Pit sculpin (Cottus pitensis)
Sculpins are bottom-dwelling fishes with large flattened heads, fanlike pectoral fins and smooth scaleless but occasionally prickly bodies. The males can be found guarding their nesting sites – usually a small “cave” under a rock or submerged log in the spring.

Shasta crayfish (Pacifastacus fortis)
The Shasta crayfish can be found in rocky areas of the river feeding on the slime coating the rocks. It demands a steady flow of fresh water to survive.

Number of endemic species: 24

LOST RIVER—Modoc and Siskiyou Counties
Lost River begins and ends in a closed basin in northern California and southwestern Oregon. This idyllic, 60-mile-long river winds through forests, meadows and fields, providing the perfect summer escape.

What to look for:
Shortnose sucker (Chasmistes brevirostris)
Chasmistes means “one who yawns,” referring to the large, flexible mouth of the sucker. Shortnose suckers are native only to the upper Klamath and Lost River basins.

Klamath pebblesnail (Fluminicola n. sp. 2)
This rare spring snail breeds only once in its lifetime and then dies. They typically have a one-year life span, with 90 percent or more of the population turning over annually. They lay their eggs in the spring and hatch in approximately 2–4 weeks.

Number of endemic species: 22

OWENS RIVER—Mono and Inyo Counties
The history-rich Owens River flows in one of the deepest valleys in America and stretches for 183 miles. This now free-flowing river is teeming with wildlife, making it a true haven for birders and nature lovers.

What to look for:
Owens tui chub (Gila bicolor snyderi)
This species evolved in the Owens River watershed with only three other smaller species of fishes: Owens pupfish (Cyprinodon radiosus), Owens speckled dace (Rhinichthys osculus ssp.) and Owens sucker (Catostomus fumeiventris).

Historically, the Owens tui chub occurred in large numbers throughout the basin, including the Owens River and associated tributaries, springs, drainage ditches and irrigation canals. However, when listed as federally endangered in 1985, only two populations of Owens tui chub were believed to exist. Owens tui chub is currently restricted to six isolated sites: Little Hot Creek Pond, Hot Creek headwaters, Sotcher Lake, Upper Owens Gorge, White Mountain Research Station and Mule Spring.

Parish’s popcorn flower (Plagiobothrys parishii)
The only endemic flower at the Owens River, this low-growing annual, sometimes called the desert popcorn flower, is from the borage family and bears a close resemblance to the common garden alyssum.

Number of endemic species: 18

SAN FRANCISCO BAY SOUTHERN STREAMS—Alameda, San Mateo, San Francisco and a portion of Santa Clara Counties
The many southern streams and creeks that feed San Francisco Bay are popular recreation spots. From the San Mateo Creek, which flows into Crystal Springs, to Coyote Creek, these waterways are rich with unusual aquatic wildlife.

What to look for:
California red-legged frog (Rana draytonii)
This frog gets its name from the red coloring on its lower abdomen and hindquarters. They are remarkable jumpers, and will quickly leap away when a threat gets too close. The California red-legged frog is the species made famous in Mark Twain’s story, “The Celebrated Jumping Frog of Calaveras County.”

Contra Costa goldfields (Lasthenia conjugens)
This glorious wildflower from the daisy family produces a sea of dime-sized flowers that can cover a broad area, creating the appearance of a rich deep-yellow carpet.

Number of endemic species: 34

A whitewater rafter’s dream, this river begins in Oregon’s High Cascades and runs across the border, emptying into the Pacific Ocean 16 miles south of California’s Crescent City. A stunning spot for a summer vacation, the river is prized by fishermen.

What to look for:
Blue chub (Gila coerulea)
The blue chub is the thinner relative in the chub family. Found only in the Upper Klamath and Lost River watersheds, this fish gets its name from the blue snouts that males don during spawning season.

Scale lanx (Lanx klamathensis)
The scale lanx is a small limpet with a thin shell many times wider than it is long. Native only to large, spring-fed lakes and streams, it’s commonly found with a variety of other rare mollusks, including the archimedes pyrg (Pyrgulopsis archimedis) and the Klamath rams-horn (Vorticifex klamathensis klamathensis).

Number of endemic species: 22

Winter Bonus


In a climate that is far too hot in the summer, the Amargosa is a winter oasis…literally. Springing from the high desert above Las Vegas, it disappears underground until it reaches the Amargosa Canyon near Death Valley National Park, where it rises to the surface, creating a vibrant green swath amidst the stark desert beauty.

What to look for:
Amargosa pupfish (Cyprinodon nevadensis)
This chunky little fish can survive in water that is as shallow as a half-inch in depth. They are adapted to a wide variety of desert temperatures, from near freezing in winter to the broiling summer sizzle. Pupfish behave as though they have a playful nature, chasing each other like young puppies.

Amargosa niterwort (Nitrophila mohavensis)
This scruffy survivor grows only in the alkaline-rich soils of the Mojave Desert. A member of the amaranth family, it sprouts a small pink flower and spreads out with rhizomes, not unlike a bamboo plant.

Number of endemic species: 39



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