Bridge conditions in Lassen County, California
108 inventoried bridges · 8 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
8 of the 108 bridges the federal inventory lists in Lassen County are rated poor; the rest split 28 good and 72 fair.
- 8 of the 108 bridges in Lassen County, California, are rated in poor condition (7.4%) in the 2025 National Bridge Inventory, as of .
- 28 bridges (25.9%) are rated good and 72 (66.7%) fair.
- The median Lassen County bridge was built in 1971.
- The busiest poor-rated bridge is CR A21 / Mooney Rd over Robbers Creek (built 1975), carrying about 1,500 vehicles a day.
Good 25.9% · Fair 66.7% · Poor 7.4% of 108 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 |
|---|---|---|---|
| CR A21 / Mooney Rd over Robbers Creek | 1975 | 1,500 | Poor |
| CR417 (punkin Ctr) over Muddy Slough No 1 | 1955 | 200 | Poor |
| CR 305 (mapes Rd) over Whitehead Slough | 1978 | 162 | Poor |
| Rd 424 (bassett) over Willow Creek | 1960 | 120 | Poor |
| Rd 304 over Whitehead Slough | 1930 | 100 | Poor |
| CR246 (belfast Rd) over Willow Creek | 1975 | 100 | Poor |
| Rd 311 over Deep Cut (baxter) Creek | 1978 | 100 | Poor |
| CR 111 (pittville) over Beaver Creek | 1975 | 100 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| State Route 36 over Susan River | 1964 | 15,300 | Fair |
| State Route 36 over Jensen Slough | 1964 | 15,300 | Good |
| State Route 36 over Gold Run Creek | 1964 | 10,300 | Good |
| U.S. Highway 395 over Long Valley Creek | 1956 | 5,500 | Fair |
| U.S. Highway 395 over UP RR & BNSF Ry | 1969 | 5,500 | Fair |
| U.S. Highway 395 over Long Valley Creek Ovfl | 1969 | 5,500 | Fair |
| U.S. Highway 395 over Willow Ranch Creek | 1969 | 5,500 | Fair |
| U.S. Highway 395 over Long Valley Creek | 1946 | 5,500 | Fair |
| U.S. Highway 395 over Long Valley Creek | 1946 | 5,500 | Good |
| U.S. Highway 395 over Galeppi Uc | 1969 | 5,500 | 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.