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)

U.S. HIGHWAY 101

Good

Over: LOST MAN CREEK

01-HUM-101-124.71, Humboldt, CA

Built 1986 Load: 32.4 t ADT: 3,700

STATE ROUTE 299

Good

Over: SOUTH FORK TRINITY RIVER

01-HUM-299-42.95, Humboldt, CA

Built 1988 Load: 32.4 t ADT: 4,400

STATE ROUTE 36

Good

Over: GRIZZLY CREEK

01-HUM-036-16.94, Humboldt, CA

Built 1996 Load: 32.4 t ADT: 1,650

U.S. HIGHWAY 101

Good

Over: NEWTON ROAD

01-HUM-101-33.22, Humboldt, CA

Built 1961 Load: 32.4 t ADT: 6,190

STATE ROUTE 36

Good

Over: VAN DUZEN RIVER

01-HUM-036-40.45, Humboldt, CA

Built 1981 Load: 32.4 t ADT: 1,000

STATE ROUTE 96

Good

Over: SUPPLY CREEK

01-HUM-096-11.62, Humboldt, CA

Built 1991 Load: 32.4 t ADT: 2,850

STATE ROUTE 96

Good

Over: MILL CREEK

01-HUM-096-R14.55, Humboldt, CA

Built 1993 Load: 32.4 t ADT: 1,505

U.S. HIGHWAY 101

Good

Over: SOUTH FORK EEL RIVER

01-HUM-101-R7.87, Humboldt, CA

Built 1969 Load: 32.4 t ADT: 5,700

STATE ROUTE 299

Good

Over: WILLOW CREEK

01-HUM-299-35.55, Humboldt, CA

Built 1956 Load: 32.4 t ADT: 3,200

U.S. HIGHWAY 101

Good

Over: HOOKER CREEK ROAD

01-HUM-101-R16.51, Humboldt, CA

Built 1965 Load: 32.4 t ADT: 6,700

STATE ROUTE 299

Good

Over: HILLSIDE

01-HUM-299-R42.30, Humboldt, CA

Built 1966 Load: 32.4 t ADT: 4,400

STATE ROUTE 169

Good

Over: ROCK CHUTE CREEK

01-HUM-169-29.83, Humboldt, CA

Built 1991 Load: 32.4 t ADT: 320

US HIGHWAY 101 NB

Good

Over: EEL RIV,EDWARDS DR,NCRRA

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

Built 1976 Load: 32.4 t ADT: 5,500

STATE ROUTE 255

Good

Over: MAD RIVER SLOUGH

01-HUM-255-R5.13, Humboldt, CA

Built 1981 Load: 32.4 t ADT: 4,300

STATE ROUTE 36

Good

Over: VAN DUZEN RIVER

01-HUM-036-17.94, Humboldt, CA

Built 1985 Load: 32.4 t ADT: 1,650

SANDY PRAIRIE ROAD

Good

Over: VAN DUZEN RIVER OVERFLOW

01-HUM-000-0.00, Humboldt, CA

Built 2009 Load: 32.4 t ADT: 30

STATE ROUTE 254

Good

Over: HILLSIDE

01-HUM-254-11.83, Humboldt, CA

Built 1989 Load: 32.4 t ADT: 565

STATE ROUTE 36

Good

Over: VAN DUZEN RIVER

01-HUM-036-R23.91, Humboldt, CA

Built 1997 Load: 32.4 t ADT: 1,200

STATE ROUTE 96

Good

Over: HOSTLER CREEK

01-HUM-096-R13.26, Humboldt, CA

Built 1992 Load: 32.4 t ADT: 1,505

STATE ROUTE 254

Good

Over: HILLSIDE

01-HUM-254-17.80-STPK, Humboldt, CA

Built 1995 Load: 32.4 t ADT: 565

STATE ROUTE 169

Good

Over: MAWAH CREEK

01-HUM-169-24.98, Humboldt, CA

Built 2012 Load: 32.4 t ADT: 2,000

STATE ROUTE 169

Good

Over: RUBE RANCH CREEK

01-HUM-169-28.49, Humboldt, CA

Built 2012 Load: 32.4 t ADT: 2,000

STATE ROUTE 169

Good

Over: MARTINS FERRY SCHOOL CRK

01-HUM-169-29.95, Humboldt, CA

Built 2012 Load: 32.4 t ADT: 345

US HIGHWAY 101 SB

Good

Over: MAD RIVER

01-HUM-101-89.63, Humboldt, CA

Built 2011 Load: 32.4 t ADT: 18,500

U.S. HIGHWAY 101

Good

Over: LITTLE LOST MAN CREEK

01-HUM-101-124.48, Humboldt, CA

Built 2020 Load: 32.4 t ADT: 4,200

US HIGHWAY 101 SB

Good

Over: JACOBY CREEK

01-HUM-101-84.50-ARC, Humboldt, CA

Built 2022 Load: 32.4 t ADT: 18,125

LANPHERE ROAD

Good

Over: MAD RIVER SLOUGH

2.5 MI WEST OF SR 101, Humboldt, CA

Built 1988 Load: 32.4 t ADT: 45

ELK RIVER ROAD

Good

Over: MARTIN SLOUGH

0.2 MI SE OF SR 101, Humboldt, CA

Built 1992 Load: 32.4 t ADT: 4,801

GLENDALE DR

Good

Over: LINDSAY CREEK

JUST NW OF FIELDBROOK RD, Humboldt, CA

Built 1995 Load: 32.4 t ADT: 1,520

GOLDEN GATE DR

Good

Over: VAN DUZEN RIVER

0.5 MI S OF SR 36, Humboldt, CA

Built 1985 Load: 32.4 t ADT: 58

WHITLOW RD

Good

Over: SONOMA CREEK

1 MI N OF SEQUOIA RD, Humboldt, CA

Built 1986 Load: 32.4 t ADT: 53

KINGS PEAK ROAD

Good

Over: NORTH FORK BEAR CREEK

2 MI S/O WILDER RIDGE RD, Humboldt, CA

Built 1993 Load: 32.4 t ADT: 75

BEAR RIVER ROAD

Good

Over: BONANZA GULCH

8.5 MI S OF MATTOLE RD, Humboldt, CA

Built 1986 Load: 32.4 t ADT: 15

MATTOLE ROAD

Good

Over: DAVIS CREEK

7.2 MI NW OF PETROLIA, Humboldt, CA

Built 1998 Load: 32.4 t ADT: 700

OLD ARCATA RD

Good

Over: JACOBY CREEK

1/4 MI N BAYSIDE CUTOFF, Humboldt, CA

Built 1988 Load: 32.4 t ADT: 3,030

MAPLE HILLS ROAD

Good

Over: SALMON CREEK

JUST S/O SALMON CREEK RD, Humboldt, CA

Built 1982 Load: 32.4 t ADT: 349

DEVOY RD

Good

Over: FRESHWATER SLOUGH

AT MYRTLE AVE, Humboldt, CA

Built 1986 Load: 32.4 t ADT: 24

MYRTLE AVE

Good

Over: FRESHWATER CR OVERFLOW

0.4 MI W OF KNEELAND RD, Humboldt, CA

Built 1984 Load: 32.4 t ADT: 6,908

RED CAP ROAD

Good

Over: BOISE CREEK

3.7 MILE S. OF SR 96, Humboldt, CA

Built 1995 Load: 32.4 t ADT: 91

PRICE CREEK ROAD

Good

Over: PRICE CREEK

0.9 MI W BLUE SLIDE ROAD, Humboldt, CA

Built 1996 Load: 32.4 t ADT: 67

LIGHTHOUSE ROAD

Good

Over: MILL CREEK

1.5 MI SW OF MATTOLE RD, Humboldt, CA

Built 2003 Load: 32.4 t ADT: 3

MATTOLE ROAD

Good

Over: INDIAN CREEK

4.5 MI S/O PETROLIA, Humboldt, CA

Built 2010 Load: 32.4 t ADT: 240

RED CAP ROAD

Good

Over: BIG ROCK GULCH

0.3 MILES SW OF SR96, Humboldt, CA

Built 2019 Load: 32.4 t ADT: 425

PORT KENYON ROAD

Good

Over: FRANCIS CREEK

0.5 MI W OF MAIN STREET, Humboldt, CA

Built 2015 Load: 32.4 t ADT: 500

IRR BIA RTE 15

Good

Over: HOSTLER CREEK

3 KM NORTH OF HOOPA, Humboldt, CA

Built 1962 Load: 32.4 t ADT: 200

STATE ROUTE 299

Good

Over: MILL CREEK

01-HUM-299-R4.21, Humboldt, CA

Built 1965 Load: 32.7 t ADT: 9,700

U.S. HIGHWAY 101

Good

Over: SORENSON ROAD

01-HUM-101-R39.67, Humboldt, CA

Built 1967 Load: 32.7 t ADT: 6,190

STATE ROUTE 96

Good

Over: BLUFF CREEK

01-HUM-096-R28.91, Humboldt, CA

Built 1967 Load: 32.7 t ADT: 540

U.S. HIGHWAY 101

Good

Over: OAKCREST COURT

01-HUM-101-R8.60, Humboldt, CA

Built 1969 Load: 33.0 t ADT: 5,700

U.S. HIGHWAY 101

Good

Over: WILLIFORD ROAD

01-HUM-101-30.50, Humboldt, CA

Built 1961 Load: 34.0 t ADT: 5,450

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