Bridge conditions in Sonoma County, California
611 inventoried bridges · 32 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
The federal inventory lists 611 bridges in Sonoma County: 138 rated good, 441 fair, and 32 poor.
- 32 of the 611 bridges in Sonoma County, California, are rated in poor condition (5.2%) in the 2025 National Bridge Inventory, as of .
- 138 bridges (22.6%) are rated good and 441 (72.2%) fair.
- The median Sonoma County bridge was built in 1967.
- The busiest poor-rated bridge is US Highway 101 over Dry Creek Road (built 1960), carrying about 45,500 vehicles a day.
Good 22.6% · Fair 72.2% · Poor 5.2% of 611 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 |
|---|---|---|---|
| US Highway 101 over Dry Creek Road | 1960 | 45,500 | Poor |
| U.S. Highway 101 over Westside Rd | 1960 | 45,500 | Poor |
| US Highway 101 SB over Chiquita Road | 1960 | 22,500 | Poor |
| Washington St over Petaluma River | 1970 | 21,900 | Poor |
| Old Redwood Hwy over Willow Brook Creek | 1999 | 19,980 | Poor |
| Arnold Drive over Sonoma Creek | 1930 | 13,900 | Poor |
| Arnold Dr over Sonoma Creek | 1924 | 13,900 | Poor |
| State Route 116 over Green Valley Creek | 1930 | 12,400 | Poor |
| River Rd over Russian River | 1914 | 10,000 | Poor |
| Old Redwood Hwy over Laguna De Santa Rosa | 1956 | 9,800 | Poor |
| River Rd over Mark West Creek | 1958 | 8,000 | Poor |
| US Highway 101 NB over First St & Cloverdale CR | 1994 | 6,800 | Poor |
| Windsor Road over Pool Creek | 1967 | 5,900 | Poor |
| Tomales Rd over Stemple Creek | 1970 | 3,000 | Poor |
| Green Valley Rd over Atascadero Creek | 1967 | 2,500 | Poor |
| Wilfred Ave over Belview-wilfred Creek | 1963 | 1,857 | Poor |
| Llano Rd over Colgan Creek | 1979 | 1,750 | Poor |
| 8TH St East over Schell Creek | 1968 | 1,500 | Poor |
| Sartori Dr over Adobe Creek | 1976 | 1,475 | Poor |
| Mill Station Rd over Atascadero CR Overflow | 1964 | 1,450 | Poor |
| Main St over Dutch Bill Creek | 1953 | 838 | Poor |
| Bloomfield Rd over Bloomfield Creek | 1917 | 524 | Poor |
| Franz Valey Sch Rd over Franz Creek | 1946 | 350 | Poor |
| Fir Road over Dutch Bill Creek | 1974 | 300 | Poor |
| Mill Creek Rd over Mill Creek | 1961 | 210 | Poor |
| Seavey Rd over No Name Creek | 1960 | 200 | Poor |
| Sweetwtr Sprngs Rd over Porter Creek | 1968 | 140 | Poor |
| Gericke Rd over Americano Creek | 1972 | 100 | Poor |
| Eagle Nest Lane over Hillside | 1930 | 100 | Poor |
| Pine Flat Rd over Sausal Creek | 1974 | 100 | Poor |
| Geysers Road over Camacho Creek | 1974 | 60 | Poor |
| Old Duncans Grd Rd over Austin Creek | 1924 | 30 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US Highway 101 over College Avenue | 2009 | 136,500 | Fair |
| U.S. Route 101 over Future Rainier Avenue | 2022 | 103,000 | Fair |
| US Highway 101 over 3RD St 4TH St & 5TH St | 1968 | 96,000 | Fair |
| US Highway 101 over Ninth Street | 1968 | 96,000 | Fair |
| U.S. Highway 101 over Santa Rosa Creek | 2009 | 96,000 | Fair |
| U.S. Highway 101 over Sixth Street | 2009 | 96,000 | Fair |
| US Highway 101 over Steele Lane | 2009 | 96,000 | Fair |
| US Highway 101 NB over Willow Brook | 1956 | 94,000 | Fair |
| US Highway 101 over Corona Ditch | 1954 | 94,000 | Good |
| US Highway 101 over Copeland Creek | 1956 | 92,000 | Fair |
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.