Bridge conditions in Marin County, California
207 inventoried bridges · 16 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
Marin County tracks close to typical: 16 of its 207 inventoried bridges (7.7%) are rated poor, against a national rate of about 7%.
- 16 of the 207 bridges in Marin County, California, are rated in poor condition (7.7%) in the 2025 National Bridge Inventory, as of .
- 91 bridges (44.0%) are rated good and 100 (48.3%) fair.
- The median Marin County bridge was built in 1959.
- The busiest poor-rated bridge is U.S. Highway 101 over Novato Creek (built 1974), carrying about 61,500 vehicles a day.
Good 44.0% · Fair 48.3% · Poor 7.7% of 207 bridges
Bridges rated poor
Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| U.S. Highway 101 over Novato Creek | 1974 | 61,500 | Poor |
| Sir Francis Drake over Lagunitas Creek | 1964 | 25,582 | Poor |
| U.S. Highway 101 over Corte Madera CR & EB Sfd | 1959 | 19,700 | Poor |
| Freitas Pkwy over U.S. Highway 101 | 1960 | 18,000 | Poor |
| Ignacio Boulevard over U.S. Highway 101 | 1964 | 12,900 | Poor |
| Lincoln Ave over San Rafael Creek | 1959 | 11,601 | Poor |
| Novato Blvd over Novato Creek | 1969 | 10,024 | Poor |
| State Route 1 over Redwood Creek | 1926 | 3,800 | Poor |
| Kerner Blvd over Indst Prk Drainage Canal | 1972 | 3,600 | Poor |
| State Route 1 over Lagunitas Creek | 1929 | 3,500 | Poor |
| Bear Valley Rd over Olema Creek | 1937 | 3,500 | Poor |
| Novato Blvd over Bowman Canyon | 1948 | 3,056 | Poor |
| Beach Rd (main St) over San Francisco Bay | 1918 | 2,000 | Poor |
| Marshall Petlum Rd over Salmon Creek | 1931 | 328 | Poor |
| Azalea Ave over Fairfax Creek | 1930 | 110 | Poor |
| Meadow Way over San Anselmo Creek | 1950 | 55 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US Highway 101 over North San Pedro Road | 1979 | 180,000 | Fair |
| U.S. Highway 101 over Lincoln Ave-n101 on Ramp | 1938 | 180,000 | Fair |
| U.S. Highway 101 over Linden Lane | 1947 | 173,000 | Good |
| U.S. Highway 101 over Ggt Bellam Andersen | 1958 | 172,000 | Good |
| U.S. Highway 101 over Corte Madera CR & Sfd Bl | 1957 | 172,000 | Fair |
| U.S. Highway 101 over Wornum Drive | 1929 | 172,000 | Good |
| U.S. Highway 101 over Nwp RR / Smart | 1957 | 167,000 | Good |
| U.S. Highway 101 over N Branch Gallinas Creek | 1951 | 159,000 | Fair |
| U.S. Highway 101 over Miller Creek | 1952 | 151,000 | Fair |
| U.S. Highway 101 over Lucas Valley Road | 1952 | 151,000 | Good |
Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.
All of California: California bridge conditions by county · every download on the data page.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.