Bridge conditions in McCook County, South Dakota
98 inventoried bridges · 7 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
McCook County tracks close to typical: 7 of its 98 inventoried bridges (7.1%) are rated poor, against a national rate of about 7%.
- 7 of the 98 bridges in McCook County, South Dakota, are rated in poor condition (7.1%) in the 2025 National Bridge Inventory, as of .
- 44 bridges (44.9%) are rated good and 47 (48.0%) fair.
- The median McCook County bridge was built in 1979.
- The busiest poor-rated bridge is 445 Ave (fas 6355) over I090 (built 1964), carrying about 328 vehicles a day.
Good 44.9% · Fair 48.0% · Poor 7.1% of 98 bridges
Bridges rated poor
Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| 445 Ave (fas 6355) over I090 | 1964 | 328 | Poor |
| 448TH Avenue over Little Vermillion River | 1940 | 173 | Poor |
| 451ST Avenue over Trib. to E Fork Verm Rv | 1930 | 66 | Poor |
| 433RD Avenue over Tributary to Wolf Creek | 1977 | 50 | Poor |
| 439TH Avenue over W. Fork of Vermillion Rv | 1961 | 45 | Poor |
| 263RD Street over Wolf Creek | 1961 | 35 | Poor |
| 248TH Street over W. Fork of Vermillion Rv | 1917 | 5 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I090 W over East Fork Vermillion Rv | 2022 | 6,819 | Good |
| I090 E over East Fork Vermillion Rv | 2021 | 6,819 | Good |
| I090 W over 453 Ave | 1964 | 6,819 | Good |
| I090 E over 453 Ave | 1964 | 6,819 | Good |
| I090 W over 448 Ave | 1964 | 6,752 | Good |
| I090 E over 448 Ave | 1964 | 6,752 | Good |
| I090 W over West Fork Vermillion Rv | 2022 | 6,497 | Good |
| I090 E over West Fork Vermillion Rv | 2021 | 6,497 | Good |
| I090 over Trib W Vermillion Rv | 2021 | 6,085 | Good |
| SD042 over East Fork Vermillion Rv | 1984 | 2,794 | Good |
Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.
All of South Dakota: South Dakota bridge conditions by county · every download on the data page.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.