Usona Road over Middle Fk Chowchilla Riv
Mariposa County, California · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Usona Road over Middle Fk Chowchilla Riv in Mariposa County, California, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 4 (poor condition) on the 0-9 scale.
- It was built in 1970, making it 55 years old at the 2025 inventory.
- It carries about 190 vehicles a day (traffic count year 1988).
- Its listed owner is the county highway agency.
- It is one of 12 of the 109 inventoried bridges in Mariposa County rated poor (11.0%); 12 (11.0%) are rated poor.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (37.42947, -119.81869)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 4 | Poor condition |
| Superstructure | 4 | Poor condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 42 ft |
| Location | 2.2 Mi South of SR 49 |
| NBI structure number | 40C0066 |
| Condition class | Poor |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
Busiest bridges in Mariposa County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| State Route 140 over Mariposa Creek | 1932 | 10,800 | Fair |
| State Route 49 over Stockton Creek | 1967 | 7,900 | Fair |
| State Route 49 over Mariposa Creek | 1942 | 6,600 | Fair |
| State Route 140 over Miles Creek | 1916 | 4,650 | Fair |
| State Route 140 over Miles Creek | 1929 | 4,650 | Fair |
| State Route 140 over Miles Creek | 1928 | 4,650 | Fair |
All bridges nearby: Mariposa County, CA bridge conditions · every bridge in Mariposa County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.