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: TURNER DRAW

01-HUM-101-89.18, Humboldt, CA

Built 1956 Load: 32.1 t ADT: 12,900

ISLAND MOUNTAIN RD

Over: CHAMISE CREEK

5.7 MI E/O BELLSPRINGS RD, Humboldt, CA

Built 1973 Load: 32.1 t ADT: 100

NISSEN LANE

Over: NISSEN SLOUGH

0.7 MI NORTH OF GOBLE LN, Humboldt, CA

Built 1952 Load: 32.1 t ADT: 13

US HIGHWAY 101 NB

Over: EEL RIVER

01-HUM-101-M53.91-RDEL, Humboldt, CA

Built 1941 Load: 32.4 t ADT: 4,400

US HIGHWAY 101 SB

Over: GANNON SLOUGH

01-HUM-101-84.70, Humboldt, CA

Built 1996 Load: 32.4 t ADT: 17,500

U.S. HIGHWAY 101

Over: PRAIRIE CREEK

01-HUM-101-122.86, Humboldt, CA

Built 1989 Load: 32.4 t ADT: 3,700

STATE ROUTE 36

Over: VAN DUZEN RIVER

01-HUM-036-13.37, Humboldt, CA

Built 1984 Load: 32.4 t ADT: 1,650

STATE ROUTE 169

Over: COON CREEK

01-HUM-169-25.81, Humboldt, CA

Built 1988 Load: 32.4 t ADT: 320

US HIGHWAY 101 SB

Over: EEL RIV,EDWARDS DR,NCRRA

01-HUM-101-R51.99, Humboldt, CA

Built 1976 Load: 32.4 t ADT: 8,200

STATE ROUTE 255

Over: MCDANIEL SLOUGH

01-HUM-255-7.77, Humboldt, CA

Built 1963 Load: 32.4 t ADT: 4,160

STATE ROUTE 255

Over: EUREKA CHANNEL

01-HUM-255-0.20-EUR, Humboldt, CA

Built 1971 Load: 32.4 t ADT: 7,300

STATE ROUTE 255

Over: MARINA ROAD

01-HUM-255-0.66-EUR, Humboldt, CA

Built 1979 Load: 32.4 t ADT: 7,300

U.S. HIGHWAY 101

Over: NEWTON B DRURY SCENIC PK

01-HUM-101-R126.10, Humboldt, CA

Built 1990 Load: 32.4 t ADT: 3,100

U.S. HIGHWAY 101

Over: BOYES CREEK

01-HUM-101-R128.97, Humboldt, CA

Built 1989 Load: 32.4 t ADT: 3,100

STATE ROUTE 96

Over: HILLSIDE

01-HUM-096-8.31, Humboldt, CA

Built 1985 Load: 32.4 t ADT: 2,900

STATE ROUTE 169

Over: MINERS CREEK

01-HUM-169-26.97, Humboldt, CA

Built 1995 Load: 32.4 t ADT: 320

STATE ROUTE 169

Over: CAPPELL CREEK

01-HUM-169-22.37, Humboldt, CA

Built 2012 Load: 32.4 t ADT: 2,000

US HIGHWAY 101 NB

Over: MAD RIVER

01-HUM-101-89.63, Humboldt, CA

Built 2012 Load: 32.4 t ADT: 16,500

DILLON ROAD

Over: SALT RIVER

N OF PORT KENYON RD, Humboldt, CA

Built 1994 Load: 32.4 t ADT: 371

HATCHERY ROAD

Over: MAD RIVER

JUST S/O BLUE LAKE, Humboldt, CA

Built 1983 Load: 32.4 t ADT: 1,016

WILDER RIDGE RD

Over: HONEYDEW CREEK

2 MI S MATTOLE RD, Humboldt, CA

Built 1990 Load: 32.4 t ADT: 189

BRIDGE ST

Over: SCOTIA MILL POND

NEAR JCT MAIN ST SCOTIA, Humboldt, CA

Built 1974 Load: 32.4 t ADT: 1,055

FORTUNA BOULEVARD

Over: STRONGS CREEK

0.2 MI N/O KENMAR RD, Humboldt, CA

Built 1949 Load: 32.4 t ADT: 11,988

BEAR CANYON ROAD

Over: SOUTH FORK EEL RIVER

0.3 MI SW/O REDWOOD DR, Humboldt, CA

Built 2000 Load: 32.4 t ADT: 158

PRICE CREEK ROAD

Over: PRICE CREEK

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

Built 1981 Load: 32.4 t ADT: 82

ALDERPOINT RD

Over: SOUTH DOBBYN CREEK

2.1 MI N ALDERPOINT, Humboldt, CA

Built 1937 Load: 32.4 t ADT: 281

DAVISON RD

Over: PRAIRIE CREEK

0.2 MI W JCT WITH SR 101, Humboldt, CA

Built 1988 Load: 32.4 t ADT: 875

KING SALMON DR

Over: KING SALMON SLOUGH

1/4 MI NW OF SR 101, Humboldt, CA

Built 1988 Load: 32.4 t ADT: 1,782

MATTOLE ROAD

Over: MCNUTT CREEK

3.6 MI NW OF PETROLIA, Humboldt, CA

Built 1996 Load: 32.4 t ADT: 180

NORTH FORK ROAD

Over: MATTOLE CREEK

1.5 MI N/O MATTOLE RD, Humboldt, CA

Built 1996 Load: 32.4 t ADT: 30

CONKLIN CREEK ROAD

Over: EAST MILL CREEK

0.2 MI E/O MATTOLE RD, Humboldt, CA

Built 2003 Load: 32.4 t ADT: 20

WILLIAMS CREEK RD

Over: WILLIAMS CREEK

0.1 MI S OF GRIZZLY BLUFF, Humboldt, CA

Built 2016 Load: 32.4 t ADT: 130

WADDINGTON RD

Over: SALT RIVER

1.1 MI N/O GRIZZLY BLUFF, Humboldt, CA

Built 2016 Load: 32.4 t ADT: 890

MATTOLE RD

Over: BULL CREEK

5.3 MI W/O HWY 101, Humboldt, CA

Built 1956 Load: 32.4 t ADT: 310

MATTOLE RD

Over: HARPER CREEK

4.3 MI W/O HWY 101, Humboldt, CA

Built 1977 Load: 32.4 t ADT: 600

REDWOOD HWY

Over: MAY CREEK

PRAIRIE CR REDWOOD ST PK, Humboldt, CA

Built 1989 Load: 32.4 t ADT: 5,450

IRR BIA RTE 541A

Over: SUPPLY CREEK

N SIDE OF HOOPA LOOP ROAD, Humboldt, CA

Built 1966 Load: 32.4 t ADT: 1,500

US HIGHWAY 101 SB

Over: ELK RIVER

01-HUM-101-74.60, Humboldt, CA

Built 1956 Load: 32.7 t ADT: 16,200

STATE ROUTE 96

Over: TRINITY RIVER

01-HUM-096-12.26, Humboldt, CA

Built 1957 Load: 32.7 t ADT: 1,505

CANNIBAL ROAD

Over: MOSLEY SLOUGH

3.7 MI W OF EEL RIVER DR., Humboldt, CA

Built 1959 Load: 32.7 t ADT: 434

PORT KENYON ROAD

Over: SALT RIVER OVERFLOW

0.24 MI W HIGHWAY 211, Humboldt, CA

Built 1962 Load: 32.7 t ADT: 351

DAVISON ROAD

Over: PRAIRIE CREEK

Approximately 0.2 miles f, Humboldt, CA

Built 1970 Load: 32.7 t ADT: 50

STATE ROUTE 96

Over: CAMP CREEK

01-HUM-096-R37.25, Humboldt, CA

Built 1949 Load: 33.4 t ADT: 1,085

BRICELAND-THORNE

Over: REDWOOD CREEK

2.3 MI W/O REDWOOD DR, Humboldt, CA

Built 1959 Load: 33.4 t ADT: 1,836

STATE ROUTE 96

Over: KLAMATH RIVER

01-HUM-096-22.95, Humboldt, CA

Built 1949 Load: 33.7 t ADT: 710

STATE ROUTE 299

Over: BLUE LAKE BLVD

01-HUM-299-R5.45, Humboldt, CA

Built 1970 Load: 33.7 t ADT: 9,700

U.S. HIGHWAY 101

Over: MAPLE HILL RD,SALMON CRK

01-HUM-101-23.89, Humboldt, CA

Built 1962 Load: 34.7 t ADT: 5,100

BRICELAND THORN RD

Over: VANARKEN CREEK

1.0 MI S SHELTER COVE RD, Humboldt, CA

Built 1961 Load: 35.0 t ADT: 420

U.S. HIGHWAY 101

Over: TRINIDAD ROAD

01-HUM-101-100.71-TRND, Humboldt, CA

Built 1960 Load: 35.3 t ADT: 4,900

U.S. HIGHWAY 101

Over: SEAWOOD DR

01-HUM-101-R103.38, Humboldt, CA

Built 1970 Load: 35.3 t ADT: 4,200

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

Related

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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 6, 2026