US 63 over Nenebec Creek
Mahaska County, Iowa · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 63 over Nenebec Creek in Mahaska County, Iowa, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1998, making it 27 years old at the 2025 inventory.
- It carries about 12,500 vehicles a day (traffic count year 2022).
- Its listed owner is the state highway agency.
- It is one of 89 of the 221 inventoried bridges in Mahaska County rated fair (40.3%); 67 (30.3%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated September 2024, on a 24-month routine inspection cycle.
- 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 → (41.20821, -92.63994)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Culvert | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous concrete culvert |
| Length | about 20 ft |
| Location | 0.2 mi. N of Jct. SR G71 |
| NBI structure number | 000000000035071 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Iowa department of transportation.
Busiest bridges in Mahaska County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Ia 163 over Muchakinok Creek | 1997 | 12,200 | Fair |
| Ia 163 over Little Muchikinock Creek | 1995 | 7,800 | Fair |
| US 63 over Little Muchakinock Creek | 1963 | 6,600 | Fair |
| Ia 92 over Spring Creek/pedestrian | 1958 | 6,400 | Fair |
| US 63 over Stream | 1982 | 6,350 | Good |
| US #63 over Muchakinock Creek | 2001 | 6,350 | Good |
All bridges nearby: Mahaska County, IA bridge conditions · every bridge in Mahaska County · Iowa bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.