Bridge conditions in Sierra County, California
66 inventoried bridges · 4 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
4 of the 66 bridges the federal inventory lists in Sierra County are rated poor; the rest split 29 good and 33 fair.
- 4 of the 66 bridges in Sierra County, California, are rated in poor condition (6.1%) in the 2025 National Bridge Inventory, as of .
- 29 bridges (43.9%) are rated good and 33 (50.0%) fair.
- The median Sierra County bridge was built in 1969.
- The busiest poor-rated bridge is Railroad Avenue over East Branch Smithneck CR (built 1987), carrying about 1,000 vehicles a day.
Good 43.9% · Fair 50.0% · Poor 6.1% of 66 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 |
|---|---|---|---|
| Railroad Avenue over East Branch Smithneck CR | 1987 | 1,000 | Poor |
| Westside Rd over South Branch Carman Crk | 1950 | 670 | Poor |
| Westside Rd over North Branch Carman Crk | 1950 | 670 | Poor |
| Packer Lake Road over Salmon Creek | 1960 | 200 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| U.S. Highway 395 over Long Valley Rd | 1976 | 4,600 | Good |
| U.S. Highway 395 over Long Valley Rd | 1976 | 2,300 | Good |
| State Route 89 over Little Truckee River | 1982 | 2,000 | Fair |
| State Route 49 over Smithneck Creek | 1965 | 1,900 | Good |
| State Route 89 over Turner Canyon | 1975 | 1,400 | Good |
| State Route 49 over Downie River | 1938 | 1,200 | Good |
| State Route 49 over Goodyears Creek | 1972 | 1,200 | Good |
| State Route 89 over Fletcher Creek | 1969 | 1,020 | Fair |
| State Route 49 over Sierraville Creek | 1962 | 1,000 | Good |
| Railroad Avenue over East Branch Smithneck CR | 1987 | 1,000 | 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.