Marin County, CA

217 public highway bridges

Marin County Bridge Snapshot

Marin County, California contains 217 public highway bridges in the FHWA National Bridge Inventory. Roughly 34.6% are rated “Good,” 35% “Fair,” 8.3% “Poor,” and 8.3% 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.

217
Total Bridges
34.6%
Good
8.3%
Poor
8.3%
Structurally Deficient

Condition Distribution

Good
34.6% (75)
Fair
35% (76)
Poor
8.3% (18)
SD
8.3% (18)

All Bridges (217)

3RD ST

Good

Over: IRWIN CREEK

AT HETHERTON ST, Marin, CA

Built 1968 Load: 24.3 t ADT: 20,000

PACIFIC WAY

Good

Over: REDWOOD CREEK

0.09 MI S SR 1, Marin, CA

Built 1956 Load: 24.3 t ADT: 75

LA GOMA ST

Good

Over: AYO CORTE MADERA DEL PRE

300 FT N OF MILLER AVE, Marin, CA

Built 1950 Load: 24.3 t ADT: 3,000

W CASTLEWOOD DRIVE

Good

Over: SAN RAFAEL BAY INLET

SW OF KNIGHT DRIVE, Marin, CA

Built 1965 Load: 24.3 t ADT: 500

STATE ROUTE 1

Good

Over: HILLSIDE

04-MRN-001-11.62, Marin, CA

Built 1982 Load: 25.3 t ADT: 4,100

U.S. HIGHWAY 101

Good

Over: WORNUM DRIVE

04-MRN-101-8.02-CMAD, Marin, CA

Built 1929 Load: 26.6 t ADT: 172,000

U.S. HIGHWAY 101

Good

Over: HILLSIDE

04-MRN-101-1.09-SAUS, Marin, CA

Built 1954 Load: 28.8 t ADT: 53,000

NICASIO VAL RD

Good

Over: ARROYO NICASIO

NEAR LUCAS VALLEY RD, Marin, CA

Built 1928 Load: 29.8 t ADT: 4,000

CHILENO VALLEY RD

Good

Over: CHILENO CREEK TRIBUTARY

4.89 MI S TMALS-PTALMA RD, Marin, CA

Built 1927 Load: 29.8 t ADT: 213

U.S. HIGHWAY 101

Good

Over: NWP RR / SMART

04-MRN-101-13.25-SRF, Marin, CA

Built 1957 Load: 32.4 t ADT: 167,000

STATE ROUTE 1

Good

Over: WALKER CREEK

04-MRN-001-44.45, Marin, CA

Built 1982 Load: 32.4 t ADT: 5,900

STATE ROUTE 1

Good

Over: STEMPLE CREEK

04-MRN-001-47.41, Marin, CA

Built 1982 Load: 32.4 t ADT: 5,900

STATE ROUTE 1

Good

Over: FALLON CREEK

04-MRN-001-47.60, Marin, CA

Built 2001 Load: 32.4 t ADT: 5,900

U.S. HIGHWAY 101

Good

Over: FRANKLIN AV & NWP RR

04-MRN-101-R20.88-NVTO, Marin, CA

Built 1974 Load: 32.4 t ADT: 61,500

ROUTE 101 SB

Good

Over: RUSH LANDING RD & NWP RR

04-MRN-101-R22.24-NVTO, Marin, CA

Built 1974 Load: 32.4 t ADT: 61,500

U.S. HIGHWAY 101

Good

Over: RUSH CREEK (S BRANCH)

04-MRN-101-R22.04-NVTO, Marin, CA

Built 1974 Load: 32.4 t ADT: 123,000

U.S. HIGHWAY 101

Good

Over: RUSH CREEK (N BRANCH)

04-MRN-101-R22.13-NVTO, Marin, CA

Built 1974 Load: 32.4 t ADT: 123,000

U.S. HIGHWAY 101

Good

Over: SAN ANTONIO CREEK

04-MRN-101-27.53, Marin, CA

Built 2019 Load: 32.4 t ADT: 96,600

STATE ROUTE 1

Good

Over: OLEMA CREEK TRIBUTARY

04-MRN-001-24.67, Marin, CA

Built 2018 Load: 32.4 t ADT: 3,650

STATE ROUTE 1

Good

Over: AMERICANO CREEK

04-MRN-001-50.44, Marin, CA

Built 2018 Load: 32.4 t ADT: 1,200

STATE ROUTE 1

Good

Over: GIACOMINI GULCH

04-MRN-001-22.78, Marin, CA

Built 2018 Load: 32.4 t ADT: 3,650

101N OFFRAMP 2 ST

Good

Over: SAN RAFAEL CREEK

04-MRN-101-10.79-SRF, Marin, CA

Built 2022 Load: 32.4 t ADT: 22,800

TOMALES PETALUMA R

Good

Over: KEYES CREEK

0.1 MI EAST OF SR 1, Marin, CA

Built 1977 Load: 32.4 t ADT: 1,200

IGNACIO BLVD

Good

Over: NCRRA\NWP RR

EAST OF US 101, Marin, CA

Built 1984 Load: 32.4 t ADT: 25,546

MEADWOOD DR

Good

Over: BRANCH CORTE MADERA CRK

IN LARKSPUR, Marin, CA

Built 1974 Load: 32.4 t ADT: 3,000

CALETA AVE

Good

Over: SLEEPY HOLLOW CREEK

200 FT E BUTTERFIELD RD, Marin, CA

Built 1989 Load: 32.4 t ADT: 500

MUIR WOODS RD

Good

Over: REDWOOD CREEK

0.7 MI N OF SR 1, Marin, CA

Built 1958 Load: 32.4 t ADT: 2,187

SLAUGHTER HOUSE RD

Good

Over: ESTERO AMERICANO

JUST SOUTH OF SR 1, Marin, CA

Built 1990 Load: 32.4 t ADT: 125

SOUTH NOVATO BLVD

Good

Over: WARNER CREEK

0.2 MI S DIABLO AVE, Marin, CA

Built 1992 Load: 32.4 t ADT: 19,460

LAGUNITAS ROAD

Good

Over: CORTE MADERA CREEK

JUST W/O SIR FRANCIS DRAK, Marin, CA

Built 2011 Load: 32.4 t ADT: 3,500

NORTH HAMILTON PKW

Good

Over: PACHECO CREEK

AT ABERDEEN RD, Marin, CA

Built 2001 Load: 32.4 t ADT: 5,000

CENTER ROAD

Good

Over: VINEYARD CREEK

AT WILMAC CT, Marin, CA

Built 2008 Load: 32.4 t ADT: 5,000

SOUTHERN HEIGHTS B

Good

Over: HILLSIDE

JCT MEYER ROAD, Marin, CA

Built 2021 Load: 32.4 t ADT: 100

PT RYES PETLUMA RD

Good

Over: NICASIO CREEK

3.47 MI E STATE HWY 1, Marin, CA

Built 1960 Load: 33.0 t ADT: 10,000

2ND ST

Good

Over: IRWIN CREEK

WEST SIDE RTE 101, Marin, CA

Built 1965 Load: 34.0 t ADT: 20,000

LUCAS VALLEY ROAD

Good

Over: MILLER CREEK

1.7 MI W OF SR 101, Marin, CA

Built 1961 Load: 35.3 t ADT: 1,000

STATE ROUTE 1

Good

Over: OLEMA CREEK

04-MRN-001-22.96, Marin, CA

Built 1928 Load: 35.6 t ADT: 2,500

INTERSTATE 580

Good

Over: SAN QUENTIN STREET

04-MRN-580-2.63-SRF, Marin, CA

Built 1957 Load: 35.6 t ADT: 67,000

DE LONG AVENUE

Good

Over: NCRRA (OLD NWP RR)

04-MRN-101-R21.15-NVTO, Marin, CA

Built 1974 Load: 39.5 t ADT: 30,155

U.S. HIGHWAY 101

Good

Over: GGT, BELLAM, ANDERSEN

04-MRN-101-9.63-SRF, Marin, CA

Built 1958 Load: 40.5 t ADT: 172,000

ATHERTON AVENUE

Good

Over: NCRRA (OLD NWP RR)

04-MRN-101-R22.04-NVTO, Marin, CA

Built 1974 Load: 41.8 t ADT: 8,800

SIMMONS AVE

Good

Over: NOVATO CREEK

0.2 MI NE NOVATO BL, Marin, CA

Built 1932 Load: 42.1 t ADT: 7,037

MRSHAL-PETALUMA RD

Good

Over: SALMON CREEK

6 MI EAST OF SR 1, Marin, CA

Built 1931 Load: 42.4 t ADT: 400

MEADOW WAY

Good

Over: SAN GERONIMO CREEK

0.5 MI S SIR FRNCS DRAKE, Marin, CA

Built 1965 Load: 42.4 t ADT: 100

LAS GALLINAS AVE

Good

Over: MILLER CREEK

0.3 MI INTX LUCAS VLY RD, Marin, CA

Built 1970 Load: 45.7 t ADT: 3,830

DIABLO AVE

Good

Over: NOVATO CREEK

AT NOVATO BLVD, Marin, CA

Built 1966 Load: 48.6 t ADT: 25,882

THORSSON COURT

Good

Over: NOVATO CREEK

0.1 MI S OF NOVATO BLVD, Marin, CA

Built 2000 Load: 54.4 t ADT: 50

TAMALPAIS AVE

Good

Over: WARNER CREEK

0.1 MI SW NOVATO BLVD, Marin, CA

Built 1973 Load: 64.8 t ADT: 4,458

LAGUNITAS RD

Good

Over: SAN GERONIMO CREEK

.03 MI S SR FRNCS DRAKE B, Marin, CA

Built 1964 Load: 67.4 t ADT: 200

MEADOW WAY

Poor

Over: SAN ANSELMO CREEK

0.1 MI SE OF CASCADE DR, Marin, CA

Built 1950 Load: 13.3 t ADT: 55

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