Mn 1 over Birch Lake Dam
Lake County, Minnesota · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Mn 1 over Birch Lake Dam in Lake County, Minnesota, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1955, making it 70 years old at the 2025 inventory.
- It carries about 650 vehicles a day (traffic count year 2019).
- Its listed owner is the state highway agency.
- It is one of 33 of the 90 inventoried bridges in Lake County rated fair (36.7%); 11 (12.2%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated May 2024, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (47.81589, -91.78413)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 251 ft |
| Location | 9.8 Mi SE of Ely |
| NBI structure number | 6845 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | May 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Minnesota department of transportation.
Busiest bridges in Lake County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Mn 61 over Stewart River | 1922 | 6,474 | Good |
| Mn 61 over Silver Creek; Pedestrian | 2022 | 6,474 | Good |
| Mn 61 over Crow Creek | 1968 | 4,763 | Fair |
| Mn 61 over Encampment River | 1941 | 4,763 | Good |
| Mn 61 over Conveyer | 1952 | 4,217 | Fair |
| Mn 61 over Conveyor Tunnel | 1978 | 4,217 | Fair |
All bridges nearby: Lake County, MN bridge conditions · every bridge in Lake County · Minnesota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.