128TH Ave SW over N. Fork Cannonball River
Slope County, North Dakota · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 128TH Ave SW over N. Fork Cannonball River in Slope County, North Dakota, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 8 (very good condition) on the 0-9 scale.
- It was built in 1983, making it 42 years old at the 2025 inventory.
- It carries about 26 vehicles a day (traffic count year 2018).
- Its listed owner is the county highway agency.
- It is one of 36 of the 43 inventoried bridges in Slope County rated good (83.7%); 0 (0.0%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its class is unchanged from 2024 (good), but component ratings moved: superstructure 7 to 8.
- Its most recent inspection on record is dated October 2024, on a 24-month routine inspection cycle.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (46.56748, -103.03081)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 8 | 8 | Very good condition |
| Superstructure | 7 | 8 | Very good condition |
| Substructure | 8 | 8 | Very good condition |
Bridge details
| Structure | Continuous prestressed concrete single box beam |
| Length | about 89 ft |
| Location | 6 North 13 East of Amidon |
| NBI structure number | 000000044149040 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | October 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the North Dakota department of transportation.
Busiest bridges in Slope County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US Highway 85 over Creek | 1991 | 1,080 | Good |
| US Highway 85 over Branch-cannonball River | 1963 | 1,010 | Good |
| US Highway 85 over Philbrick Creek | 1937 | 920 | Good |
| US Highway 12 over Little Missouri River | 1950 | 580 | Fair |
| US Highway 12 over Bnrr Separation | 1984 | 561 | Good |
| US Highway 12 over Little Beaver Creek | 1987 | 520 | Good |
All bridges nearby: Slope County, ND bridge conditions · every bridge in Slope County · North Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.