Marin County, CA

217 public highway bridges

Marin County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Marin County, California contains 217 public highway bridges. Roughly 34.6% are rated “Good,” 35% “Fair,” and 8.3% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

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

217
Total Bridges
34.6%
Good
35%
Fair
8.3%
Poor Condition

Condition Distribution

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

All Bridges (217)

BEACH RD (MAIN ST)

Poor

Over: SAN FRANCISCO BAY

INTERSECTION BEACH & MAIN, Marin, CA

Built 1918 Load: 13.6 t ADT: 2,000

SAUNDERS AVE

Poor

Over: SAN ANSELMO CREEK

IN SAN ANSELMO, Marin, CA

Built 1935 Load: 15.2 t ADT: 3,000

CENTER BLVD

Poor

Over: SAN ANSELMO CREEK

16M NW OF SAN ANSELMO AVE, Marin, CA

Built 1935 Load: 15.2 t ADT: 12,000

AZALEA AVE

Poor

Over: FAIRFAX CREEK

80 FT W OF ARROYO RD, Marin, CA

Built 1930 Load: 15.6 t ADT: 110

STATE ROUTE 1

Poor

Over: REDWOOD CREEK

04-MRN-001-6.02, Marin, CA

Built 1926 Load: 16.2 t ADT: 3,900

KERNER BLVD

Poor

Over: INDST PRK DRAINAGE CANAL

N/O IRENE ST, S/O BELLAM, Marin, CA

Built 1972 Load: 18.3 t ADT: 3,600

STATE ROUTE 1

Poor

Over: LAGUNITAS CREEK

04-MRN-001-28.51, Marin, CA

Built 1929 Load: 20.4 t ADT: 3,500

SIR FRANCIS DRAKE

Poor

Over: LAGUNITAS CREEK

1.9 MI E SR 1 AT OLEMA, Marin, CA

Built 1964 Load: 26.6 t ADT: 5,000

BEAR VALLEY RD

Poor

Over: OLEMA CREEK

0.04 MI W OF S.H. 1, Marin, CA

Built 1937 Load: 27.5 t ADT: 3,500

LINCOLN AVE

Poor

Over: SAN RAFAEL CREEK

700 FT S OF IRWIN AVE, Marin, CA

Built 1959 Load: 30.5 t ADT: 11,601

MIDDLE RD

Poor

Over: ESTERO DE SAN ANTONIO

4.5 MI FROM S.R. 1, Marin, CA

Built 1958 Load: 32.7 t ADT: 40

U.S. HIGHWAY 101

Poor

Over: CORTE MADERA CR & EB SFD

04-MRN-101-8.47-LKSP, Marin, CA

Built 1959 Load: 33.0 t ADT: 19,700

NOVATO BLVD

Poor

Over: NOVATO CREEK

0.5 MILE S OF SUTRO AVE., Marin, CA

Built 1969 Load: 35.0 t ADT: 10,024

NOVATO BLVD

Poor

Over: BOWMAN CANYON

1 MILE N INTXN SUTRO AVE., Marin, CA

Built 1948 Load: 37.3 t ADT: 3,056

U.S. HIGHWAY 101

Poor

Over: NOVATO CREEK

04-MRN-101-R20.51-NVTO, Marin, CA

Built 1974 Load: 39.9 t ADT: 61,500

MARSHALL PETLUM RD

Poor

Over: SALMON CREEK

3.0MI W OF HICKSVALLEY RD, Marin, CA

Built 1931 Load: 48.3 t ADT: 328

ALEXANDER AVE

Poor

Over: BUNKER ROAD

0.3 KM EAST OF RTE 101, Marin, CA

Built 1938 Load: 67.7 t ADT: 7,201

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

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.