SD251 over Ponca Ck
Gregory County, South Dakota · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- SD251 over Ponca Ck in Gregory 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 1984, making it 41 years old at the 2025 inventory.
- It carries about 400 vehicles a day (traffic count year 2024).
- Its listed owner is the state highway agency.
- It is one of 15 of the 51 inventoried bridges in Gregory County rated good (29.4%); 5 (9.8%) 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 → (43.18872, -99.43516)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 7 | Good condition |
| Superstructure | 7 | Good condition |
| Substructure | 7 | Good condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 60 ft |
| Location | 2.6 S Jst US 18 |
| NBI structure number | 000000027050216 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Gregory County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| 345 Avenue over South Fork Whetstone Ck | 2001 | 560 | Good |
| SD047 over Ck | 1957 | 552 | Fair |
| SD047 over Ck | 1957 | 552 | Fair |
| SD044 over Bull Ck | 1971 | 540 | Good |
| SD044 over Lone Tree Ck | 1971 | 540 | Fair |
| SD044 over Dixon Ck | 1971 | 540 | Fair |
All bridges nearby: Gregory County, SD bridge conditions · every bridge in Gregory County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.