Bridge conditions in Lyon County, Iowa
273 inventoried bridges · 70 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
Of the 273 Lyon County bridges in the federal inventory, 70 carry a poor rating. That 25.6% share is roughly 4x the national average.
- 70 of the 273 bridges in Lyon County, Iowa, are rated in poor condition (25.6%) in the 2025 National Bridge Inventory, as of .
- 104 bridges (38.1%) are rated good and 99 (36.3%) fair.
- The median Lyon County bridge was built in 1978.
- The busiest poor-rated bridge is A26 (180TH St) over Big Sioux River (built 1977), carrying about 1,017 vehicles a day.
Good 38.1% · Fair 36.3% · Poor 25.6% of 273 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 |
|---|---|---|---|
| A26 (180TH St) over Big Sioux River | 1977 | 1,017 | Poor |
| FM over Klondike Creek | 1962 | 1,017 | Poor |
| FM over Rock River | 1966 | 977 | Poor |
| FM over Nelson Creek | 1966 | 789 | Poor |
| FM over Overflow | 1969 | 718 | Poor |
| FM over Little Rock River | 1954 | 709 | Poor |
| FM over Mud Creek | 1968 | 688 | Poor |
| FM over Mud Creek | 1961 | 509 | Poor |
| L14 over Turner Creek | 1964 | 509 | Poor |
| L14 over Tom Creek | 1964 | 509 | Poor |
| L14 over Dry Run Creek | 1964 | 509 | Poor |
| FM over Dry Run Creek | 1964 | 469 | Poor |
| FM over Mud Creek | 1970 | 450 | Poor |
| FM over Rock River | 1970 | 399 | Poor |
| FM over Little Rock River | 1955 | 369 | Poor |
| FM over Kanaranzi Creek | 1959 | 369 | Poor |
| N Boone St over Moon Creek | 1958 | 354 | Poor |
| N 2ND Ave over Small Stream | 1900 | 346 | Poor |
| Local Road over Rock River | 1968 | 337 | Poor |
| FM over Klondike Creek | 1966 | 309 | Poor |
| FM over Riggs Creek | 1970 | 290 | Poor |
| FM over Mud Creek | 1970 | 290 | Poor |
| FM over Small Stream | 1972 | 240 | Poor |
| W Indiana Ave over Rio Grande Creek | 1940 | 232 | Poor |
| FM over West Rat Creek | 1965 | 230 | Poor |
| K60(INDIAN Ave) over Little Rock River | 1960 | 230 | Poor |
| FM over Plum Creek | 1968 | 210 | Poor |
| FM over Rat Creek | 1966 | 199 | Poor |
| FM over Little Otter Creek | 1968 | 199 | Poor |
| FM over Overflow | 1968 | 199 | Poor |
| FM over Blood Run Creek | 1971 | 180 | Poor |
| FM over Little Rock River | 1968 | 131 | Poor |
| Local Road over Blood Run Creek | 1900 | 90 | Poor |
| Local Road over Little Rock River | 1900 | 71 | Poor |
| Local Road over Little Rock River | 1900 | 62 | Poor |
| Local over Rock River | 1900 | 62 | Poor |
| Local Road over Lizard Creek | 1900 | 62 | Poor |
| Local Road over Small Stream | 1900 | 62 | Poor |
| Local Road over Pinney Creek | 1900 | 62 | Poor |
| Local Road over Moon Creek | 1900 | 62 | Poor |
| Local Road over Willow Creek | 1940 | 50 | Poor |
| Local Road over Hefferman Creek | 1900 | 46 | Poor |
| Local Road over Argo Slough | 1900 | 46 | Poor |
| Local Road over Mud Creek | 1900 | 46 | Poor |
| Local Road over Small Stream | 1900 | 41 | Poor |
| Local Road over Albertson Creek | 1900 | 41 | Poor |
| Local Road over Klondike Creek | 1900 | 41 | Poor |
| Local Road over Klondike Creek | 1900 | 41 | Poor |
| Local Road over Emery Creek | 1900 | 35 | Poor |
| Local Road over Otter Creek | 1900 | 30 | Poor |
| Local Road over over Flow | 1900 | 30 | Poor |
| Local Road over Taft Creek | 1900 | 30 | Poor |
| Local Road over Rat Creek | 1954 | 26 | Poor |
| Local Road over Allen Creek | 1900 | 26 | Poor |
| Local Road over Little Otter Creek | 1900 | 26 | Poor |
| Local Road over Overflow | 1900 | 26 | Poor |
| Local Road over Emery Creek | 1900 | 26 | Poor |
| Local Road over Argo Slough | 1900 | 26 | Poor |
| Local Road over Taft Creek | 1900 | 26 | Poor |
| Local Road over Small Stream | 1900 | 26 | Poor |
| Local Road over Willow Creek | 1900 | 26 | Poor |
| Local Road over Rat Creek | 1900 | 21 | Poor |
| Local Road over Overflow | 1900 | 21 | Poor |
| Local Road over Small Stream | 1900 | 21 | Poor |
| Local Road over Emery Creek | 1900 | 15 | Poor |
| Local Road over Tom Creek | 1900 | 15 | Poor |
| Local Road over Tom Creek | 1974 | 15 | Poor |
| Local Road over Hefferman Creek | 1900 | 11 | Poor |
| Side Ditch Ent over Side Ditch | 1900 | 10 | Poor |
| Local Road over Johnson Creek | 1900 | 5 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Ia 9 over Stream | 1980 | 4,840 | Good |
| Ia 9 over Stream | 1940 | 4,520 | Fair |
| Ia 9 over Bloodrun Creek | 1977 | 4,520 | Fair |
| US 75 & Ia 9 over Moon Creek | 1972 | 4,400 | Fair |
| Ia 9 over Rock River | 1974 | 3,920 | Fair |
| Ia 9 over Mud Creek | 1975 | 3,270 | Fair |
| Ia 9 over Stream | 1982 | 3,180 | Fair |
| Ia 9 over over BNSF RR | 1982 | 3,180 | Fair |
| Ia 9 over Moon Creek | 1974 | 3,180 | Fair |
| US 75 over Rock River | 1975 | 2,620 | 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.