300 Street over Lost Ck
Tripp County, South Dakota · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 300 Street over Lost Ck in Tripp County, South Dakota, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 2002, making it 23 years old at the 2025 inventory.
- It carries about 36 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 29 of the 89 inventoried bridges in Tripp County rated good (32.6%); 22 (24.7%) are rated poor.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (43.05345, -99.95476)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 7 | Good condition |
| Superstructure | 8 | Very good condition |
| Substructure | 8 | Very good condition |
Bridge details
| Structure | Prestressed concrete tee beam |
| Length | about 40 ft |
| Location | 1.5S & 0.7E Millboro |
| NBI structure number | 000000062147500 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Tripp County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US018 over Dog Ear Ck | 1965 | 3,553 | Fair |
| US018 Ser Rd over Ck | 1965 | 2,820 | Fair |
| US018 over Sand Ck | 1973 | 2,052 | Fair |
| US018 over Ck | 1973 | 1,803 | Fair |
| US018 over Cottonwood Ck | 1965 | 1,746 | Fair |
| US018 over Big Hollow Ck | 1965 | 1,746 | Good |
All bridges nearby: Tripp County, SD bridge conditions · every bridge in Tripp County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.