Humboldt County, CA

398 public highway bridges

Humboldt County Bridge Snapshot

Humboldt County, California contains 398 public highway bridges in the FHWA National Bridge Inventory. Roughly 32.9% are rated “Good,” 48.7% “Fair,” 6.3% “Poor,” and 6.3% are classified as structurally deficient — the federal designation for spans whose deck, superstructure, or substructure has been rated 4 or below on the 0–9 NBI scale. Structurally deficient does not mean unsafe to cross; it means the bridge is on the priority list for repair or replacement.

Inspections in CA are conducted by certified engineers from the state Department of Transportation on a 24-month cycle, and results are reported back to the FHWA each spring. The list below shows every NBI-tracked bridge in the county, sorted by inventory load rating. Use the “Sort by” controls to surface the lowest-rated spans first, and click any row for full inspection history, traffic counts, and condition trends.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

398

Total Bridges

32.9%

Good

6.3%

Poor

6.3%

Structurally Deficient

Condition Distribution

Good

32.9% (131)

Fair

48.7% (194)

Poor

6.3% (25)

SD

6.3% (25)

All Bridges (398)

Sort:

U.S. HIGHWAY 101

Over: JONES SLOUGH

01-HUM-101-88.87, Humboldt, CA

Built 1959 Load: 14.3 t ADT: 12,900

BRICELAND-THORNE

Over: REDWOOD CREEK

3.3 MI W JCT US 101, Humboldt, CA

Built 1938 Load: 14.3 t ADT: 1,836

ALDERPOINT ROAD

Over: COOPER CREEK

30.4 MI E/N S.H. 101, Humboldt, CA

Built 1952 Load: 14.3 t ADT: 250

ELK RIVER ROAD

Over: NORTH FORK ELK RIVER

NE PEPPER ST, Humboldt, CA

Built 1923 Load: 14.6 t ADT: 156

PRICE CREEK ROAD

Over: PRICE CREEK

0.2 MI W/O BLUE SLIDE RD, Humboldt, CA

Built 1940 Load: 14.6 t ADT: 118

ARLINGTON AVENUE

Over: FRANCIS CREEK

JUST W SR 211 IN FERNDALE, Humboldt, CA

Built 2001 Load: 15.2 t ADT: 500

COFFEE CREEK ROAD

Over: PERRY SLOUGH

0.2 MI SOUTH OF RTE 211, Humboldt, CA

Built 1931 Load: 15.6 t ADT: 254

STATE ROUTE 36

Over: YAGER CREEK

01-HUM-036-4.86, Humboldt, CA

Built 1968 Load: 15.9 t ADT: 2,800

BRICELAND RD

Over: REDWOOD CREEK

10 MI E SHELTER COVE RD, Humboldt, CA

Built 1935 Load: 16.2 t ADT: 1,836

MAPLE CREEK ROAD

Over: BOULDER CREEK

1/4 MI E BUTLER VLY RD, Humboldt, CA

Built 1923 Load: 16.2 t ADT: 106

ALDERPOINT RD

Over: MARTIN CREEK

6.7 MI SOUTH BRIDGEVILLE, Humboldt, CA

Built 1972 Load: 16.2 t ADT: 124

JACK SHAW ROAD

Over: BILLINGS CREEK

1.3 MI E MOUNTAIN VIEW, Humboldt, CA

Built 1987 Load: 16.2 t ADT: 50

12TH ST

Over: ROHNER CREEK

0.1 MILE NORTH NEWBURG RD, Humboldt, CA

Built 1935 Load: 16.2 t ADT: 3,160

MAIN STREET

Over: ROHNER CREEK

JUST EAST OF 16TH STREET, Humboldt, CA

Built 1922 Load: 16.5 t ADT: 11,181

HOLMES FLAT RD

Over: EEL RIVER

NEAR HOLMES, Humboldt, CA

Built 1999 Load: 16.7 t ADT: 100

ETSBRG HNYDEW RD

Over: MATTOLE RIVER

5.77 MI N/O THORNE RD, Humboldt, CA

Built 1928 Load: 16.8 t ADT: 200

HOWE CREEK ROAD

Over: HOWE CREEK

2.1 MI S/O BLUE SLIDE RD, Humboldt, CA

Built 2006 Load: 16.8 t ADT: 19

FULMOR ROAD

Over: SALT RIVER

NORTH OF KENYON ROAD, Humboldt, CA

Built 1950 Load: 17.2 t ADT: 246

REDWOOD DR

Over: DEAN CREEK

N/O REDWAY ADJ TO US 101, Humboldt, CA

Built 1933 Load: 17.2 t ADT: 1,978

SHOWER PASS RD

Over: OLSEN CREEK

6.1 MI NE/O KNEELAND RD, Humboldt, CA

Built 1966 Load: 17.2 t ADT: 7

STATE ROUTE 96

Over: HILLSIDE

01-HUM-096-8.26, Humboldt, CA

Built 1985 Load: 17.5 t ADT: 2,900

ZANES RD

Over: ELK RIVER

0.1 MI W ELK RIVER RD, Humboldt, CA

Built 1936 Load: 17.5 t ADT: 38

OLD MATTOLE RD

Over: MCNUTT CREEK

0.49 MI N OF MATTOLE RD, Humboldt, CA

Built 1926 Load: 17.5 t ADT: 100

BERTA RD

Over: ELK RIVER

0.14 MI W ELK RIVER RD, Humboldt, CA

Built 1936 Load: 17.8 t ADT: 518

ALBERT ETTER RA RD

Over: BEAR CREEK

0.2 MI SW/O ETRSBG-HNYDW, Humboldt, CA

Built 1985 Load: 17.8 t ADT: 50

BAIR ROAD

Over: REDWOOD CREEK

3.4 MI N/O SR 299, Humboldt, CA

Built 1950 Load: 18.1 t ADT: 113

BRICELAND ROAD

Over: REDWOOD CREEK

0.1 MI E BRICELND THO RD, Humboldt, CA

Built 1949 Load: 18.1 t ADT: 250

WHITLOW ROAD

Over: SONOMA CREEK #2

2.4 MI E OF ELK CREEK RD, Humboldt, CA

Built 1966 Load: 18.8 t ADT: 53

WHITLOW ROAD

Over: SONOMA CREEK #1

2.2 MI E OF ELK CREEK RD, Humboldt, CA

Built 1966 Load: 18.8 t ADT: 53

FOREST ROAD

Over: SOUTH FORK EEL RIVER

0.1 MI W/O REDWOOD DR, Humboldt, CA

Built 1965 Load: 18.8 t ADT: 110

ELINOR ROAD

Over: GREENLOW CREEK

0.3 MILE NE OF ROUTE 254, Humboldt, CA

Built 1988 Load: 19.1 t ADT: 20

MATTOLE RD

Over: DRY CREEK

1 MI S/O SINGLEY CREEK, Humboldt, CA

Built 1985 Load: 19.4 t ADT: 196

ALDERPOINT RD

Over: CONLEY CREEK

1 MI S OF BLOCKSBURG, Humboldt, CA

Built 1990 Load: 20.1 t ADT: 114

BRICELAND-THORNE

Over: MCKEE CREEK

0.1 MI S/O SHELTER COVE, Humboldt, CA

Built 1952 Load: 20.1 t ADT: 420

STATE ROUTE 283

Over: EEL RIVER & NWP RR

01-HUM-283-0.12, Humboldt, CA

Built 1941 Load: 20.4 t ADT: 2,150

HOWARD HEIGHTS RD

Over: FRESHWATER CREEK

0.01 MI SW FRESHWATER RD, Humboldt, CA

Built 1949 Load: 20.4 t ADT: 172

BROOKWOOD DRIVE

Over: JACOBY CREEK

0.1 MI S/O JACOBY CRK RD, Humboldt, CA

Built 1967 Load: 20.4 t ADT: 162

STATE ROUTE 299

Over: EAST FORK WILLOW CREEK

01-HUM-299-33.21, Humboldt, CA

Built 1956 Load: 20.7 t ADT: 3,200

STATE ROUTE 255

Over: SAMOA CHANNEL

01-HUM-255-1.37-EUR, Humboldt, CA

Built 1971 Load: 20.7 t ADT: 7,300

BRICELAND ROAD

Over: REDWOOD CREEK (REDWAY)

WHITTEMORE STATE PARK, Humboldt, CA

Built 1938 Load: 20.7 t ADT: 260

COUNTRY CLUB RD

Over: TRINITY RIVER

IN WILLOW CREEK, Humboldt, CA

Built 1957 Load: 21.1 t ADT: 2,947

MATTOLE ROAD

Over: NORTH FORK MATTOLE RIVER

1.3 NW OF MATTOLE RIVER, Humboldt, CA

Built 1961 Load: 21.1 t ADT: 219

BRICELAND-THORNE

Over: SOUTH FORK EEL RIVER

1.1 MI W JCT OLD RTE 101, Humboldt, CA

Built 1966 Load: 21.4 t ADT: 2,468

STATE ROUTE 299

Over: WILLOW CREEK

01-HUM-299-34.56, Humboldt, CA

Built 1955 Load: 21.7 t ADT: 3,200

ISHI PISHI RD

Over: KLAMATH RIVER

0.5 MI SW OF SR 96, Humboldt, CA

Built 1967 Load: 21.7 t ADT: 71

BUTLER VALLEY RD

Over: MAD RIVER

0.1 MI E/O BLACK CRK LN, Humboldt, CA

Built 1937 Load: 22.0 t ADT: 105

WEST END ROAD

Over: WARREN CREEK

0.2 MI S WARREN CREEK RD, Humboldt, CA

Built 1927 Load: 22.0 t ADT: 472

ROHNERVILLE ROAD

Over: STRONGS CREEK

0.3 MI W OF NEWBURG RD, Humboldt, CA

Built 1915 Load: 22.4 t ADT: 4,924

US HIGHWAY 101 SB

Over: EUREKA SLOUGH

01-HUM-101-79.78-EUR, Humboldt, CA

Built 1943 Load: 22.7 t ADT: 17,000

U.S. HIGHWAY 101

Over: GREENLAW CREEK

01-HUM-101-R45.57, Humboldt, CA

Built 1966 Load: 22.7 t ADT: 6,100

Read our methodology — how this data is sourced, computed, and verified.

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Data sourced from official U.S. government datasets. See our methodology for details. Retrieved and formatted by PlainBridges Editorial

Reviewed byPlainbridges Editorial, Plain Bridges Editorial Team · June 5, 2026