450TH Avenue over Lake St. John Outlet
Hamlin County, South Dakota · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 450TH Avenue over Lake St. John Outlet in Hamlin County, South Dakota, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1930 and reconstructed in 1979, making it 95 years old at the 2025 inventory.
- It carries about 324 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 28 of the 61 inventoried bridges in Hamlin County rated fair (45.9%); 7 (11.5%) are rated poor.
- 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 → (44.54916, -97.20914)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 5 | Fair condition |
Bridge details
| Structure | Continuous concrete culvert |
| Length | about 29 ft |
| Location | 2.6S of Lake Norden |
| NBI structure number | 000000029140176 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Hamlin County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I029 S over 462 Ave | 1973 | 4,595 | Fair |
| I029 N over 462 Ave | 1973 | 4,595 | Fair |
| I029 S over Stray Horse Ck | 1973 | 4,595 | Fair |
| I029 N over Stray Horse Ck | 1973 | 4,595 | Fair |
| I029 S over SD022 | 1973 | 4,595 | Fair |
| I029 N over SD022 | 1973 | 4,595 | Fair |
All bridges nearby: Hamlin County, SD bridge conditions · every bridge in Hamlin County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.