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)

U.S. HIGHWAY 101

Unknown

Over: CORTE MADERA CR & SFD BL

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

Built 1957 ADT: 15,000

U.S. HIGHWAY 101

Unknown

Over: CORTE MADERA CR & SFD BL

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

Built 1961 ADT: 32,990

U.S. HIGHWAY 101

Unknown

Over: SR 1, RICH BY, FRNTGE RD

04-MRN-101-4.03-SAUS, Marin, CA

Built 1957 ADT: 30,500

N101-SAN PEDRO RD

Unknown

Over: NORTH SAN PEDRO ROAD

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

Built 1970 ADT: 16,800

U.S. HIGHWAY 101

Unknown

Over: LINCOLN AVE-N101 ON RAMP

04-MRN-101-12.19-SRF, Marin, CA

Built 1938 ADT: 25,100

U.S. HIGHWAY 101

Unknown

Over: LINDEN LANE

04-MRN-101-11.64-SRF, Marin, CA

Built 1947 ADT: 7,500

U.S. HIGHWAY 101

Unknown

Over: 2ND, 3RD, 4TH, 5TH, MSSN

04-MRN-101-10.72-SRF, Marin, CA

Built 1965 ADT: 12,900

U. S. HIGHWAY 101

Unknown

Over: 2ND, 3RD, 4TH, 5TH, MSSN

04-MRN-101-10.72-SRF, Marin, CA

Built 1941 ADT: 36,900

U.S. HIGHWAY 101

Unknown

Over: SAUSALITO ROAD

04-MRN-101-0.32-SAUS, Marin, CA

Built 1935 ADT: 10,415

U.S. HIGHWAY 101

Unknown

Over: DONAHUE ST/N. BRIDGE BLD

04-MRN-101-3.33-SAUS, Marin, CA

Built 1943 ADT: 5,920

PEDESTRIAN WALKWAY

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-11.41-SRF, Marin, CA

Built 1969 ADT: 173,000

U.S. HIGHWAY 101

Unknown

Over: LUCAS VALLEY ROAD

04-MRN-101-14.71-SRF, Marin, CA

Built 1952 ADT: 15,950

SB101-E580 CONNECT

Unknown

Over: US HIGHWAY 101

04-MRN-101-9.94-SRF, Marin, CA

Built 2009 ADT: 165,000

WOLFBACK RIDGE RD

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-1.52-SAUS, Marin, CA

Built 1954 ADT: 106,000

U.S. HIGHWAY 101

Unknown

Over: US 101 ON & OFF RAMPS

04-MRN-101-1.68-SAUS, Marin, CA

Built 1954 ADT: 1,676

STATE ROUTE 131

Unknown

Over: US HIGHWAY 101

04-MRN-131-0.01, Marin, CA

Built 1956 ADT: 133,000

TAMALPAIS DRIVE

Unknown

Over: US HIGHWAY 101

04-MRN-101-7.37-CMAD, Marin, CA

Built 1957 ADT: 166,000

STATE ROUTE 580

Unknown

Over: BELLAM BOULEVARD

04-MRN-580-4.50-SRF, Marin, CA

Built 1959 ADT: 29,468

STATE ROUTE 580

Unknown

Over: BELLAM BOULEVARD

04-MRN-580-4.50-SRF, Marin, CA

Built 2010 ADT: 29,468

SIR FRAN DRAKE BLV

Unknown

Over: STATE ROUTE 580

04-MRN-580-3.29-SRF, Marin, CA

Built 1957 ADT: 67,000

PEDESTRIAN WALKWAY

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-4.75-CMAD, Marin, CA

Built 1957 ADT: 133,000

PEDESTRIAN WALKWAY

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-8.29-LKSP, Marin, CA

Built 1959 ADT: 172,000

STATE ROUTE 37

Unknown

Over: ATHERTON AVENUE

04-MRN-037-13.77, Marin, CA

Built 1959 ADT: 4,510

STATE ROUTE 37

Unknown

Over: ATHERTON AVENUE

04-MRN-037-13.77, Marin, CA

Built 1959 ADT: 4,510

FREITAS PKWY

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-13.71-SRF, Marin, CA

Built 1960 ADT: 1,700

W37-N101 CONNECTOR

Unknown

Over: NOVATO BL-N101, NWP RR

04-MRN-037-R11.23-NVTO, Marin, CA

Built 1964 ADT: 3,800

W37-S101&N101 OFF

Unknown

Over: COUNTY RD, US 101, NWPRR

04-MRN-037-R11.20-NVTO, Marin, CA

Built 1964 ADT: 900

MILLER CREEK ROAD

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-15.57, Marin, CA

Built 1961 ADT: 5,000

IGNACIO BOULEVARD

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-18.09-NVTO, Marin, CA

Built 1964 ADT: 5,000

CLAY ST / NAVE DR

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-16.64-NVTO, Marin, CA

Built 1964 ADT: 150,000

S101-E37 & NOVATO-

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-18.88-NVTO, Marin, CA

Built 1964 ADT: 143,000

S NOVATO BLVD

Unknown

Over: W37-S101 CONNECTOR RAMP

04-MRN-101-18.94-NVTO, Marin, CA

Built 1964 ADT: 11,000

ROWLAND BOULEVARD

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-R20.19-NVTO, Marin, CA

Built 1974 ADT: 123,000

DE LONG AVENUE

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-R21.11-NVTO, Marin, CA

Built 1974 ADT: 123,000

U.S. HWY 101 SB

Unknown

Over: OLIVE AVENUE

04-MRN-101-R21.47-NVTO, Marin, CA

Built 1974 ADT: 4,400

U.S. HWY 101 NB

Unknown

Over: OLIVE AVENUE

04-MRN-101-R21.47-NVTO, Marin, CA

Built 1974 ADT: 4,400

ATHERTON AVENUE

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-R22.00-NVTO, Marin, CA

Built 1974 ADT: 123,000

ROUTE 101 NB

Unknown

Over: RUSH LANDING RD & NWP RR

04-MRN-101-R22.27-NVTO, Marin, CA

Built 1974 ADT: 2,000

N&S101-E37 CONNCTR

Unknown

Over: S NOVATO BL,N101 & NWPRR

04-MRN-101-18.96-NVTO, Marin, CA

Built 1964 ADT: 800

MERRYDALE ROAD

Unknown

Over: US 101 & MERRYDALE RD

04-MRN-101-13.50-SRF, Marin, CA

Built 1996 ADT: 167,000

S101 ON & OFF RAMP

Unknown

Over: U.S. HIGHWAY 101

04-MRN-101-25.50, Marin, CA

Built 2006 ADT: 80,000

PEDESTRIAN BIKEWAY

Unknown

Over: LINDEN LANE

04-MRN-000-0.00, Marin, CA

Built 2010 ADT: 7,500

PEDESTRIAN WALKWAY

Unknown

Over: SIR FRANCIS DRAKE BLVD

1.4 MI W OF SR 101, Marin, CA

Built 1968 ADT: 10,000

PEDESTRIAN WALKWAY

Unknown

Over: PARADISE DRIVE

INTX UPLAND CIRCLE INTRX, Marin, CA

Built 1970 ADT: 2,730

BIKE PATH

Unknown

Over: BELLAM BLVD

UNDER U.S. HIGHWAY 101, Marin, CA

Built 1930 ADT: 2,500

PEDESTRIAN WALKWAY

Unknown

Over: NICASIO VALLEY RD

0.15 MI N SIR FRNCS DK B2, Marin, CA

Built 1960 ADT: 1,330

PEDESTRIAN WALKWAY

Unknown

Over: SIR FRANCIS DRAKE BLVD

1/4 MI E OF US 101, Marin, CA

Built 1981 ADT: 10,000

BIKE PATH

Unknown

Over: SIR FRANCIS DRAKE BLVD

SAM P TAYLOR STATE PARK, Marin, CA

Built 1980 ADT: 2,500

HORSE CREEK CAMP R

Fair

Over: OLEMA CREEK

3.2 miles south of Olema,, Marin, CA

Built 1960 Load: 9.1 t ADT: 20

MILL CROSSING

Fair

Over: LAGUNITAS CREEK

SAMUEL P TAYLOR STATE PK, Marin, CA

Built 1947 Load: 10.4 t ADT: 1

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.