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)

Sort:

ENTERPRISE CONCRSE

Over: COYOTE CREEK TRIBUTARY

.02 MI W TENNESSEE VLY RD, Marin, CA

Built 1950 Load: 13.0 t ADT: 70

STATE PARK ROAD

Over: LAGUNITAS CREEK

SAMUEL P TAYLOR STATE PK, Marin, CA

Built 1947 Load: 13.3 t ADT: 50

SIR-FRANCIS DRAKE

Over: CORTE MADERA CR(DRAKE)

3.5 MI W SR 101 SN ANSLM, Marin, CA

Built 1929 Load: 14.9 t ADT: 34,000

WINSHIP ROAD

Over: CORTE MADERA CREEK

0.03 MI E/O SIR FRAN DRK, Marin, CA

Built 1909 Load: 14.9 t ADT: 2,000

SAN ANTONIO RD

Over: SOUTH SAN ANTONIO CREEK

0.6 MI N OF US 101, Marin, CA

Built 1917 Load: 15.2 t ADT: 200

BARBER AVE

Over: CORTE MADERA CREEK

0.1 MI E OF FRANCIS DRAKE, Marin, CA

Built 1930 Load: 15.2 t ADT: 1,500

CENTER BLVD

Over: SAN ANSELMO CREEK

AT SYCAMORE AVE, Marin, CA

Built 1940 Load: 15.2 t ADT: 14,000

BRIDGE AVE

Over: SAN ANSELMO CREEK

80M SW OF SIR FRANCIS DRK, Marin, CA

Built 1935 Load: 15.2 t ADT: 9,000

ALEXANDER AVE

Over: ABANDONED NWP RR ROW

0.1 MI E OF MAGNOLIA AVE, Marin, CA

Built 1925 Load: 15.2 t ADT: 1,570

NICASSIO VLY RD

Over: HALLECK CREEK

1 MI N LUCAS VLY RD, Marin, CA

Built 1931 Load: 15.6 t ADT: 2,000

CREEK ROAD

Over: SAN ANSELMO CREEK

AT DOMINGA AVE, Marin, CA

Built 1929 Load: 15.6 t ADT: 255

MAIN GATE ROAD

Over: SMART RAILROAD

0.37 MI E HWY 101, Marin, CA

Built 1930 Load: 15.6 t ADT: 5,000

STATE ROUTE 1

Over: LAGUNITAS CREEK OVERFLOW

04-MRN-001-28.39, Marin, CA

Built 1929 Load: 16.2 t ADT: 3,000

STATE ROUTE 1

Over: LAGUNITAS CREEK OVERFLOW

04-MRN-001-28.56, Marin, CA

Built 1929 Load: 16.2 t ADT: 3,000

STATE ROUTE 1

Over: ELLIS CREEK

04-MRN-001-34.97, Marin, CA

Built 1931 Load: 16.2 t ADT: 2,300

STATE ROUTE 1

Over: TOMASINI CANYON

04-MRN-001-29.85, Marin, CA

Built 1925 Load: 16.2 t ADT: 2,300

SUTRO AVE

Over: NOVATO CREEK

0.1 MI S NOVATO BLVD, Marin, CA

Built 1935 Load: 16.2 t ADT: 7,153

WILSON HILL RD

Over: ARROYO SAUSAL TRIBUTARY

0.22 MI W PT RYS-PETLMA R, Marin, CA

Built 1928 Load: 16.2 t ADT: 330

MONTEZUMA RD

Over: SAN GERONIMO CREEK

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

Built 1938 Load: 16.2 t ADT: 50

MARIN DR

Over: FAIRFAX CREEK

AT BOTHIN RD, Marin, CA

Built 1930 Load: 16.2 t ADT: 110

U.S. HIGHWAY 101

Over: GOLDEN GATE-SAN FRAN BAY

04-MRN-101-L0.01, Marin, CA

Built 1937 Load: 16.5 t ADT: 112,000

MADRONE AVE

Over: SAN ANSELMO CREEK

150 FT E OF NOKOMIS, Marin, CA

Built 1930 Load: 16.5 t ADT: 1,500

SUMMIT AVE

Over: HILLSIDE

1.4 MI INTRX LOVELL AVE, Marin, CA

Built 1980 Load: 16.8 t ADT: 257

GLENWOOD AVE

Over: ROSS CREEK

JUST N/O LAGUNITAS RD, Marin, CA

Built 1909 Load: 16.8 t ADT: 2,370

SPRUCE RD

Over: FAIRFAX CREEK

50 FT W OF ARROYO RD, Marin, CA

Built 1930 Load: 16.8 t ADT: 255

LOCUST AVE

Over: AYO CORTE MADERA DEL PRE

250 FT N OF MILLER AVE, Marin, CA

Built 1934 Load: 17.3 t ADT: 4,500

ALEXANDER AVENUE

Over: EAST ROAD

1.3 KM EAST OF SR 101, Marin, CA

Built 1938 Load: 17.8 t ADT: 7,201

PT REYES PETLMA RD

Over: NICASIO CREEK

3.2 MI E OF SR 1, Marin, CA

Built 1937 Load: 18.5 t ADT: 6,000

SIR-FRANCIS DRAKE

Over: DEVILS GULCH

4.4 MI E OF SR 1, Marin, CA

Built 1920 Load: 19.4 t ADT: 3,000

MOUNT LASSEN DR SB

Over: MILLER CREEK

0.06 MI N LUCAS VALLEY RD, Marin, CA

Built 1925 Load: 21.1 t ADT: 980

MUIR WOODS RD

Over: REDWOOD CREEK

2.0 MI N OF SR 1, Marin, CA

Built 1946 Load: 22.4 t ADT: 2,090

SIR-FRANCIS DRAKE

Over: LAGUNITAS CREEK

5.9 MI E OF SH 1, Marin, CA

Built 1929 Load: 23.0 t ADT: 2,000

SIR-FRANCIS DRAKE

Over: LAGUNITAS CREEK

SHAFTER BRIDGE, Marin, CA

Built 1982 Load: 23.3 t ADT: 3,000

NICASSIO VLY RD

Over: NICASIO DRAIN NO 2

S PT. REYES - PETALM, Marin, CA

Built 1968 Load: 24.3 t ADT: 1,750

BEL MARIN KEYS BL

Over: ARROYO SAN JOSE

JUST N COMMERCIAL DR, Marin, CA

Built 1970 Load: 24.3 t ADT: 20,883

BEL MARIN KEYS BL

Over: NOVATO CREEK DRAIN

1 MI NW NAVE DR, Marin, CA

Built 1960 Load: 24.3 t ADT: 6,838

IGNACIO BLVD

Over: ARROYO SAN JOSE

0.4 MI W US 101, Marin, CA

Built 1960 Load: 24.3 t ADT: 11,820

REDWOOD BLVD

Over: DUTTON SLOUGH

0.1 MI SE ROWLAND BL, Marin, CA

Built 1968 Load: 24.3 t ADT: 3,641

MOUNTAIN VIEW AVE

Over: SAN GEROMINO CREEK

INT SIR FRANCIS DRAKE BL, Marin, CA

Built 1962 Load: 24.3 t ADT: 100

POINT SAN RAFAEL R

Over: SAN RAFAEL BAY INLET

BY INTERSECT OF KNIGHT DR, Marin, CA

Built 1955 Load: 24.3 t ADT: 2,400

U.S. HIGHWAY 101

Over: HILLSIDE

04-MRN-101-1.19-SAUS, Marin, CA

Built 1954 Load: 24.5 t ADT: 53,000

U.S. HIGHWAY 101

Over: MILLER CREEK

04-MRN-101-15.35, Marin, CA

Built 1952 Load: 24.6 t ADT: 151,000

FLAMINGO RD

Over: COYOTE CREEK

0.17 MI N MARINE AVE, Marin, CA

Built 1964 Load: 25.3 t ADT: 1,705

STINSON BEACH ROAD

Over: EASKOOT CREEK

West from US Route 101 on, Marin, CA

Built 1959 Load: 26.3 t ADT: 150

GRAND AVE

Over: SAN RAFAEL CREEK

500 FT E OF US HWY 101, Marin, CA

Built 1965 Load: 27.5 t ADT: 19,800

STATE ROUTE 1

Over: ESKOOT CREEK

04-MRN-001-12.37, Marin, CA

Built 1957 Load: 30.1 t ADT: 4,100

U.S. HIGHWAY 101

Over: ARROYO DE SAN JOSE

04-MRN-101-18.15, Marin, CA

Built 1928 Load: 30.8 t ADT: 139,000

BUNKER ROAD

Over: RODEO LAGOON

From US Route 101 take Sa, Marin, CA

Built 1983 Load: 30.8 t ADT: 600

MT MCKINLEY RD

Over: MILLER CREEK

LUCAS VLY RD INTERSECTION, Marin, CA

Built 1963 Load: 31.1 t ADT: 800

U.S. HIGHWAY 101

Over: N BRANCH GALLINAS CREEK

04-MRN-101-13.99-SRF, Marin, CA

Built 1951 Load: 32.4 t ADT: 159,000

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

Related

Browse all → | Rankings →

Data sourced from official U.S. government datasets. See our methodology for details. Retrieved and formatted by PlainBridges Editorial

Reviewed byPlainbridges Editorial, Plain Bridges Editorial Team · June 5, 2026