Bridge conditions in Decatur County, Iowa
199 inventoried bridges · 78 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
Of the 199 Decatur County bridges in the federal inventory, 78 carry a poor rating. That 39.2% share is roughly 6x the national average.
- 78 of the 199 bridges in Decatur County, Iowa, are rated in poor condition (39.2%) in the 2025 National Bridge Inventory, as of .
- 37 bridges (18.6%) are rated good and 84 (42.2%) fair.
- The median Decatur County bridge was built in 1970.
- The busiest poor-rated bridge is US 69 over Zadie Creek (built 1925), carrying about 610 vehicles a day.
Good 18.6% · Fair 42.2% · Poor 39.2% of 199 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.
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Rest Area Road over Rest Area Road | 1994 | 13,800 | Fair |
| SB I-35 over Grand River | 1970 | 7,700 | Fair |
| NB I-35 over Grand River | 1970 | 7,550 | Fair |
| SB I-35 over 310TH Street | 1970 | 7,250 | Fair |
| SB I-35 over Stream | 1970 | 7,250 | Good |
| NB I-35 over 310TH St | 1970 | 7,100 | Fair |
| NB I-35 over Stream | 1970 | 7,100 | Fair |
| NB I-35 over Stream | 1970 | 7,100 | Fair |
| SB I-35 over 324TH Street | 1970 | 7,000 | Fair |
| NB I-35 over 324TH Street | 1970 | 6,900 | Fair |
Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.
Every bridge in Decatur County → - all 199, busiest first, each with its own condition record.
All of Iowa: Iowa 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.