39120 305th Street over Mosquito Creek
PoorPosted for loadCharles Mix County, South Dakota · 8.0S & 3.8W of Wagner · Structure no. 000000012472370
- Built
- 1920
- 105 years old, rebuilt 1983
- Condition
- Poor
- inspected October 2023
- Type
- Tee Beam
- Prestressed Concrete
- Length
- 46 ft
- 1 main span
- Daily traffic
- 48
- 2022 count
- Owner
- County
- County Highway Agency
About this bridge
39120 305th Street over Mosquito Creek is a prestressed concrete tee beam carrying 39120 305th Street over Mosquito Creek in Charles Mix County, South Dakota. It was built in 1920 and reconstructed in 1983, so it is 105 years old, older than the South Dakota average of 48.9 years.
The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.
It carries about 48 vehicles a day, roughly 2% of them trucks, projected to reach 48 by 2032. The structure is 46 ft (14.1 m) long and 16 ft wide. If it were closed, the detour would be 3.7 mi (6 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 4 Poor | Advanced section loss, deterioration, spalling or scour. |
| Channel and channel protection | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was 39120 305th Street over Mosquito Creek built?
It was built in 1920, making it 105 years old in 2025. It was reconstructed in 1983.
What condition is 39120 305th Street over Mosquito Creek in?
The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in October 2023.
How much traffic does 39120 305th Street over Mosquito Creek carry?
About 48 vehicles per day (2022 count), of which roughly 2% are trucks.
How long is 39120 305th Street over Mosquito Creek?
The structure is 46 ft (14.1 m) long with a longest span of 45 ft (13.7 m) and a deck 16 ft wide.
Who owns 39120 305th Street over Mosquito Creek?
It is owned by the County Highway Agency.