Mn 78 over Otter Tail River
FairOtter Tail County, Minnesota · 4.9 MI N of S JCT TH 108 · Structure no. 9406
- Built
- 1959
- 66 years old
- Condition
- Fair
- inspected August 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 143 ft
- 3 main spans
- Daily traffic
- 4,649
- 2021 count
- Owner
- State
- State Highway Agency
About this bridge
Mn 78 over Otter Tail River is a prestressed concrete stringer/multi-beam or girder carrying Mn 78 over Otter Tail River in Otter Tail County, Minnesota. It was built in 1959, so it is 66 years old, older than the Minnesota average of 38.5 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 4,649 vehicles a day, roughly 18% of them trucks, projected to reach 4,500 by 2041. The structure is 143 ft (43.7 m) long and 35 ft wide.
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 | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Mn 78 over Otter Tail River built?
It was built in 1959, making it 66 years old in 2025.
What condition is Mn 78 over Otter Tail River 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 Mn 78 over Otter Tail River carry?
About 4,649 vehicles per day (2021 count), of which roughly 18% are trucks.
How long is Mn 78 over Otter Tail River?
The structure is 143 ft (43.7 m) long with a longest span of 47 ft (14.2 m) and a deck 35 ft wide.
Who owns Mn 78 over Otter Tail River?
It is owned by the State Highway Agency.