Bridge conditions in Napa County, California
160 inventoried bridges · 8 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
The federal inventory lists 160 bridges in Napa County: 71 rated good, 81 fair, and 8 poor.
- 8 of the 160 bridges in Napa County, California, are rated in poor condition (5.0%) in the 2025 National Bridge Inventory, as of .
- 71 bridges (44.4%) are rated good and 81 (50.6%) fair.
- The median Napa County bridge was built in 1966.
- The busiest poor-rated bridge is State Route 29 over Nvrr Napa River Stanly (built 1977), carrying about 48,000 vehicles a day.
Good 44.4% · Fair 50.6% · Poor 5.0% of 160 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 |
|---|---|---|---|
| State Route 29 over Nvrr Napa River Stanly | 1977 | 48,000 | Poor |
| State Route 29 SB over Suscol Creek | 1981 | 32,500 | Poor |
| State Route 29 over Garnett Creek | 1902 | 12,000 | Poor |
| Knoxv-berryessa Rd over Pope Crk.(lake Berryessa | 1957 | 3,570 | Poor |
| Deer Park Road over Napa River | 1966 | 3,115 | Poor |
| Dry CR Rd over Dry Creek | 1920 | 2,490 | Poor |
| State Route 128 over Hopper Slough | 1921 | 2,075 | Poor |
| Greenwood Ave over Garnett Creek | 1904 | 162 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| State Route 29 over State Route 221 (soscol) | 2024 | 79,300 | Good |
| State Route 29 over American Canyon Creek | 1943 | 48,000 | Fair |
| State Route 29 over Nvrr Napa River Stanly | 1977 | 48,000 | Poor |
| State Route 29 over Stanley Creek | 1981 | 48,000 | Fair |
| State Route 29 over Dry Creek | 1970 | 43,000 | Fair |
| St Rte 29 Byway E over Craig Creek | 1958 | 43,000 | Good |
| State Route 29 over Perfume Creek | 1963 | 43,000 | Good |
| State Route 29 SB over Napa Creek | 1964 | 33,500 | Good |
| State Route 29 NB over Napa Creek | 1949 | 33,500 | Good |
| State Route 29 SB over Suscol Creek | 1981 | 32,500 | Poor |
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.