Bridge conditions in Clinton County, Iowa
375 inventoried bridges · 12 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
Clinton County tracks close to typical: 12 of its 375 inventoried bridges (3.2%) are rated poor, against a national rate of about 7%.
- 12 of the 375 bridges in Clinton County, Iowa, are rated in poor condition (3.2%) in the 2025 National Bridge Inventory, as of .
- 261 bridges (69.6%) are rated good and 102 (27.2%) fair.
- The median Clinton County bridge was built in 1991.
- The busiest poor-rated bridge is Harts Mill Rd over Mill Creek (built 1970), carrying about 1,410 vehicles a day.
Good 69.6% · Fair 27.2% · Poor 3.2% of 375 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.
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Harts Mill Rd over Mill Creek | 1970 | 1,410 | Poor |
| Elvira Rd over Mill Creek | 1962 | 1,360 | Poor |
| 290TH Ave over Ames Creek | 1971 | 1,220 | Poor |
| Second Ave Rd over Little Mill Creek | 1935 | 450 | Poor |
| 44TH Ave over Rock Creek | 1985 | 370 | Poor |
| 432ND Avenue over Elk River | 1968 | 310 | Poor |
| 235TH Street over Wapsipinicon River | 1930 | 100 | Poor |
| 235TH Street over Branch of Wapsipinicon | 1930 | 100 | Poor |
| 100TH St. over Union Creek | 1900 | 78 | Poor |
| 308TH Ave. over Sugar Creek | 1985 | 70 | Poor |
| 300TH Ave over Ames Creek | 1912 | 16 | Poor |
| 130TH Avenue over Yankee Run Creek | 1968 | 10 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 61 over Dd #15 | 1981 | 17,600 | Good |
| US 30 & 67 over Mill Creek | 2000 | 17,300 | Fair |
| US 30 & US 67 over over UPRR | 2000 | 17,200 | Good |
| US 67 over over UP RR | 1978 | 11,200 | Fair |
| US 30 over Mississippi Rvr RR S 2ND | 1956 | 11,100 | Fair |
| Ia 136 over Mississippi River & RR | 1974 | 11,000 | Fair |
| US 61 over Stream | 1996 | 10,600 | Good |
| US 61 over Stream | 1996 | 9,800 | Good |
| US 61 over Stream | 1996 | 9,600 | Good |
| US 30 over Drainage Ditch | 1974 | 9,400 | Fair |
Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.
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.