SD1804 over Cow Ck
Sully County, South Dakota · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- SD1804 over Cow Ck in Sully County, South Dakota, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 7 (good condition) on the 0-9 scale.
- It was built in 2007, making it 18 years old at the 2025 inventory.
- It carries about 632 vehicles a day (traffic count year 2024).
- Its listed owner is the state highway agency.
- It is one of 14 of the 31 inventoried bridges in Sully County rated good (45.2%); 6 (19.4%) 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 → (44.55529, -100.44637)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 7 | Good condition |
Bridge details
| Structure | Continuous concrete culvert |
| Length | about 24 ft |
| Location | 0.4 N Hughes Co Line |
| NBI structure number | 000000060129235 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Sully County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US083 over Okobojo Ck | 1998 | 1,490 | Good |
| 185 St over Ck | 2017 | 760 | Good |
| SD1804 over Okobojo Ck | 1972 | 632 | Fair |
| SD1804 over Ck | 1995 | 261 | Good |
| 291 Avenue over Okobojo Ck | 1936 | 250 | Fair |
| 176 Street over Okobojo Ck | 2023 | 230 | Good |
All bridges nearby: Sully County, SD bridge conditions · every bridge in Sully County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.