US 18 over Little Sioux Overflow
FairClay County, Iowa · 3.6 Mi. E of E Jct. US 71 · Structure no. 000000000020350
- Built
- 1931
- 94 years old, rebuilt 1965
- Condition
- Fair
- inspected August 2023
- Type
- Stringer/Multi-beam or Girder
- Steel
- Length
- 42 ft
- 1 main span
- Daily traffic
- 4,170
- 2022 count
- Owner
- State
- State Highway Agency
About this bridge
US 18 over Little Sioux Overflow is a steel stringer/multi-beam or girder carrying US 18 over Little Sioux Overflow in Clay County, Iowa. It was built in 1931 and reconstructed in 1965, so it is 94 years old, older than the Iowa average of 45.5 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
It carries about 4,170 vehicles a day, roughly 16% of them trucks, projected to reach 4,170 by 2043. The structure is 42 ft (12.8 m) long and 49 ft wide. If it were closed, the detour would be 3.1 mi (5 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US 18 over Little Sioux Overflow built?
It was built in 1931, making it 94 years old in 2025. It was reconstructed in 1965.
What condition is US 18 over Little Sioux Overflow in?
The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in August 2023.
How much traffic does US 18 over Little Sioux Overflow carry?
About 4,170 vehicles per day (2022 count), of which roughly 16% are trucks.
How long is US 18 over Little Sioux Overflow?
The structure is 42 ft (12.8 m) long with a longest span of 40 ft (12.2 m) and a deck 49 ft wide.
Who owns US 18 over Little Sioux Overflow?
It is owned by the State Highway Agency.