Bridge conditions in Trinity County, California
194 inventoried bridges · 7 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
The federal inventory lists 194 bridges in Trinity County: 112 rated good, 75 fair, and 7 poor.
- 7 of the 194 bridges in Trinity County, California, are rated in poor condition (3.6%) in the 2025 National Bridge Inventory, as of .
- 112 bridges (57.7%) are rated good and 75 (38.7%) fair.
- The median Trinity County bridge was built in 1973.
- The busiest poor-rated bridge is Hyampom Road over Little Creek (built 1955), carrying about 330 vehicles a day.
Good 57.7% · Fair 38.7% · Poor 3.6% of 194 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 |
|---|---|---|---|
| Hyampom Road over Little Creek | 1955 | 330 | Poor |
| Summit Creek Road over Carr Creek | 1987 | 300 | Poor |
| State Route 3 over Coffee Creek Overflow | 1968 | 230 | Poor |
| Steiner Flat Road over Dutton Creek | 1950 | 100 | Poor |
| Wildwood-mad River over Dubakella Creek | 1972 | 50 | Poor |
| May over Rattlesnake Creek | 1959 | 50 | Poor |
| Price Creek Rd over Price Creek | 1950 | 20 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| State Route 299 over East Weaver Creek | 1962 | 7,125 | Fair |
| State Route 299 over Weaver Creek | 1953 | 5,375 | Fair |
| State Route 299 over Little Browns Creek | 1999 | 5,375 | Good |
| State Route 299 over Trinity River | 1980 | 4,450 | Fair |
| State Route 299 over Indian Creek | 1974 | 4,050 | Fair |
| State Route 299 over Gray Creek | 1966 | 3,800 | Fair |
| State Route 299 over Trinity River | 1990 | 3,800 | Fair |
| State Route 299 over Trinity River | 1991 | 3,800 | Good |
| State Route 299 over Manzanita Creek | 1923 | 3,650 | Good |
| State Route 299 over Grass Valley Creek | 1962 | 3,500 | 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.