I 90 over Irrigation Canal
Big Horn County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- I 90 over Irrigation Canal in Big Horn County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1971, making it 54 years old at the 2025 inventory.
- It carries about 8,516 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 90 of the 133 inventoried bridges in Big Horn County rated fair (67.7%); 5 (3.8%) are rated poor.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (45.73356, -107.5678)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 5 | Fair condition |
Bridge details
| Structure | Steel culvert |
| Length | about 25 ft |
| Location | 3.1M S Hardin |
| NBI structure number | I00090498+04621 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Big Horn County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Irr-s 47 over Int W Hardin I 90 | 1970 | 5,396 | Fair |
| Irr - I 90 over Int Dunmore | 1959 | 4,473 | Fair |
| Irr - I 90 over Int Dunmore | 1959 | 4,473 | Fair |
| Irr - I 90 over Bighorn River | 1971 | 4,258 | Good |
| Irr - I 90 over Bighorn River | 1971 | 4,258 | Fair |
| Irr - I 90 over Sarpy Road-s 384 | 1971 | 4,258 | Fair |
All bridges nearby: Big Horn County, MT bridge conditions · every bridge in Big Horn County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.