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)

STATE ROUTE 37 WB

Fair

Over: NOVATO CREEK

04-MRN-037-11.96-NVTO, Marin, CA

Built 1959 Load: 32.4 t ADT: 17,000

STATE ROUTE 37 EB

Fair

Over: NOVATO CREEK

04-MRN-037-11.96-NVTO, Marin, CA

Built 1959 Load: 32.4 t ADT: 17,000

STATE ROUTE 37

Fair

Over: SIMONDS SLOUGH

04-MRN-037-13.04-NVTO, Marin, CA

Built 1959 Load: 32.4 t ADT: 34,000

STATE ROUTE 37

Fair

Over: PETALUMA RIVER

04-MRN-037-14.47, Marin, CA

Built 1958 Load: 32.4 t ADT: 34,000

US HIGHWAY 101

Fair

Over: NORTH SAN PEDRO ROAD

04-MRN-101-12.69-SRF, Marin, CA

Built 1979 Load: 32.4 t ADT: 180,000

U.S. HIGHWAY 101

Fair

Over: FRANKLIN AV & NWP RR

04-MRN-101-R20.89-NVTO, Marin, CA

Built 1974 Load: 32.4 t ADT: 61,500

State Route 1

Fair

Over: MILLERTON GULCH

04-MRN-001-33.40, Marin, CA

Built 1997 Load: 32.4 t ADT: 2,300

OLEMA-BOLINAS RD

Fair

Over: PINE GULCH CREEK

1.3 MI S OF SR 1, Marin, CA

Built 1986 Load: 32.4 t ADT: 2,076

ALEXANDER RD

Fair

Over: STEMPLE CREEK

0.39 MI N TMALS-PETLMA RD, Marin, CA

Built 1962 Load: 32.4 t ADT: 60

MOUNT LASSEN DR NB

Fair

Over: MILLER CREEK

0.06 MI N LUCAS VALLEY RD, Marin, CA

Built 1965 Load: 32.4 t ADT: 980

CANYON ROAD

Fair

Over: SAN ANSELMO CREEK

0.1 MI S/O CASCADE DR, Marin, CA

Built 1998 Load: 32.4 t ADT: 100

BRIDGEGATE DR

Fair

Over: MILLER CREEK

0.1 MI N LUCAS VALLEY RD, Marin, CA

Built 1987 Load: 32.4 t ADT: 500

DOHERTY DR

Fair

Over: ARROYO HOLON

AT ROSE LANE, Marin, CA

Built 2014 Load: 32.4 t ADT: 6,381

ANDERSEN DRIVE

Fair

Over: MAHON CREEK

W OF ANDERSEN & LINDARO, Marin, CA

Built 1997 Load: 32.4 t ADT: 3,500

STATE ROUTE 1

Fair

Over: COYOTE CREEK

04-MRN-001-0.42, Marin, CA

Built 1954 Load: 32.7 t ADT: 30,500

VLY-FRD-FRKLN SCH

Fair

Over: ESTERO AMERICANO

0.85 MI S OF S.R. 1, Marin, CA

Built 1961 Load: 34.0 t ADT: 100

VLY FD FRNKLIN SCH

Fair

Over: ESTERO DE SAN ANTONIO

0.2 MI S WHITAKER BLUF RD, Marin, CA

Built 1964 Load: 35.0 t ADT: 100

PT REYES PETLMA RD

Fair

Over: SAN ANTONIO CREEK

AT MARIN SONOMA CO LINE, Marin, CA

Built 1964 Load: 35.3 t ADT: 1,450

STATE ROUTE 1

Fair

Over: OLEMA CREEK

04-MRN-001-22.81, Marin, CA

Built 1928 Load: 35.6 t ADT: 2,900

SIR-FRANCIS DRAKE

Fair

Over: SAN GERONIMO CREEK

7.6 MI E OF SR 1, Marin, CA

Built 1929 Load: 36.3 t ADT: 3,500

W SAN FRANCISCO BL

Fair

Over: SAN RAFAEL CREEK

JUST S/O SECOND ST, Marin, CA

Built 1981 Load: 39.2 t ADT: 50

MOUNT SHASTA DR

Fair

Over: MILLER CREEK

0.08 MI N LUCAS VALLEY RD, Marin, CA

Built 1962 Load: 39.9 t ADT: 500

SIR FRANCIS DRAKE

Fair

Over: WHITE'S HILL TRAIL

0.6 MI N/O BAYWOOD CYN RD, Marin, CA

Built 2002 Load: 43.4 t ADT: 3,500

LUCAS VALLEY RD

Fair

Over: MILLER CREEK

0.87 MI N OF SR 101, Marin, CA

Built 1959 Load: 49.2 t ADT: 6,500

U.S. HIGHWAY 101

Good

Over: IRWIN CREEK

04-MRN-101-11.20-SRF, Marin, CA

Built 1895 Load: 14.6 t ADT: 129,000

NOKOMIS AVE

Good

Over: SAN ANSELMO CREEK

300 FT N MADRONE AVE, Marin, CA

Built 1930 Load: 15.2 t ADT: 400

ROWLAND WAY

Good

Over: NOVATO CREEK

0.25 MI N ROWLAND BLVD, Marin, CA

Built 1992 Load: 15.9 t ADT: 2,735

PT REYES PETLMA RD

Good

Over: ARROYO SAUSAL(CHSE FACT)

0.5 MI S INTX NWTO BL, Marin, CA

Built 1933 Load: 16.2 t ADT: 2,590

SIR FRANCIS DRAKE

Good

Over: CORTE MADERA CREEK

3.0 MI E OF US HWY 101, Marin, CA

Built 1926 Load: 16.2 t ADT: 32,300

NORWOOD AVE

Good

Over: ROSS CREEK

0.1 MI NORTH OF SHADY LN, Marin, CA

Built 1908 Load: 16.5 t ADT: 1,200

SHADY LANE

Good

Over: ROSS CREEK

NEAR LOCUST ST, Marin, CA

Built 1909 Load: 16.8 t ADT: 1,800

SIR FRANCIS DRAKE

Good

Over: OLEMA CREEK

0.32 MI W SH 1, Marin, CA

Built 1930 Load: 16.8 t ADT: 3,000

REDWOOD BLVD

Good

Over: NOVATO CREEK

0.6 M N ROWLAND BL, Marin, CA

Built 1947 Load: 18.1 t ADT: 9,103

REDWOOD BLVD

Good

Over: NOVATO CREEK

0.6 M N ROWLAND BL, Marin, CA

Built 1929 Load: 20.1 t ADT: 9,103

FALLON-TWO ROCK RD

Good

Over: ESTERO DE SAN ANTONIO

0.02 MI E SR 1, Marin, CA

Built 1932 Load: 20.1 t ADT: 249

COLLEGE AVE

Good

Over: CORTE MADERA CREEK

0.2 MI SO SIR FRNCS DRAKE, Marin, CA

Built 1970 Load: 20.4 t ADT: 6,000

MRSHAL PETALUMA RD

Good

Over: SAN ANTONIO CREEK

0.27 MI E CHILENO VLY RD, Marin, CA

Built 1929 Load: 20.7 t ADT: 328

GRANT AVE

Good

Over: NOVATO CREEK

AT VIRGINIA AVENUE, Marin, CA

Built 1936 Load: 21.1 t ADT: 6,711

DIABLO BLVD

Good

Over: WARNER CREEK

0.1 MI SW OF NOVATO BLVD, Marin, CA

Built 1970 Load: 21.4 t ADT: 7,723

MARSHALL-PETALUMA

Good

Over: SALMON CREEK

0.3M W OF HICKSVALLEY RD, Marin, CA

Built 1928 Load: 21.4 t ADT: 328

SEVENTH ST

Good

Over: NOVATO CREEK

N OF NOVATO BLVD, Marin, CA

Built 1971 Load: 21.7 t ADT: 7,729

CAMINO ALTO

Good

Over: AYO CORTE MADERA DEL PRE

0.15 MI N MILLER AVE, Marin, CA

Built 1970 Load: 22.4 t ADT: 4,000

STATE ROUTE 1

Good

Over: HILLSIDE

04-MRN-001-11.63, Marin, CA

Built 1982 Load: 22.7 t ADT: 3,900

TWIN BRIDGE RD

Good

Over: STEMPLE CREEK

0.22 MI N TMLES-PETLUM RD, Marin, CA

Built 1958 Load: 24.0 t ADT: 80

NICASIO VLY RD

Good

Over: NICASIO DRAIN #1

12.4 MI N OF HWY 101, Marin, CA

Built 1968 Load: 24.3 t ADT: 1,750

LUCKY DRIVE

Good

Over: BRANCH CORTE MADERA CRK

IN CORTE MADERA, Marin, CA

Built 1970 Load: 24.3 t ADT: 3,000

LINDARO ST

Good

Over: MAHON CREEK

SOUTH OF ANDERSEN DR, Marin, CA

Built 1962 Load: 24.3 t ADT: 5,735

REDWOOD HWY

Good

Over: GALLINAS CREEK

IN SAN RAFAEL, Marin, CA

Built 1969 Load: 24.3 t ADT: 16,000

FREITAS PRKY

Good

Over: GALLINAS CREEK

0.3 MI W US HWY 101, Marin, CA

Built 1950 Load: 24.3 t ADT: 8,738

LAS GALINAS AV

Good

Over: GALLINAS CREEK

AT FREITAS PKWY, Marin, CA

Built 1965 Load: 24.3 t ADT: 6,871

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