Bridge conditions in Clay County, South Dakota
93 inventoried bridges · 14 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
About one in 7 bridges in Clay County is rated in poor condition: 14 of 93 on the federal inventory, one of the higher shares in South Dakota.
- 14 of the 93 bridges in Clay County, South Dakota, are rated in poor condition (15.1%) in the 2025 National Bridge Inventory, as of .
- 38 bridges (40.9%) are rated good and 41 (44.1%) fair.
- The median Clay County bridge was built in 1996.
- The busiest poor-rated bridge is 700 S. Dakota Ave. over Vermillion Rv (built 1975), carrying about 550 vehicles a day.
Good 40.9% · Fair 44.1% · Poor 15.1% of 93 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 |
|---|---|---|---|
| 700 S. Dakota Ave. over Vermillion Rv | 1975 | 550 | Poor |
| 46230 306 St. over Vermillion Rv Overflow | 1970 | 150 | Poor |
| 45530 306 Street over Ck | 1971 | 147 | Poor |
| 46080 313 St. over Clay Ck | 1983 | 125 | Poor |
| 46080 314 St. over Clay Ck Ditch | 1900 | 97 | Poor |
| 46530 314TH St. over Vermillion Rv | 1930 | 97 | Poor |
| 46540 307TH St. over Baptist Ck | 1940 | 97 | Poor |
| 46580 313 St. over Vermillion Rv | 1910 | 40 | Poor |
| 31500 455 Ave over Yankton Clay Ditch | 1938 | 25 | Poor |
| 29830 Ash Crk Ave. over Ash Ck | 1945 | 25 | Poor |
| 45980 303 St. over Vermillion Rv | 1909 | 15 | Poor |
| 46380 308 St over Vermillion Rv | 1930 | 15 | Poor |
| 46600 313 St. over Ck | 1925 | 15 | Poor |
| 46610 305TH St. over Baptist Ck | 1935 | 15 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| SD050 over Sd 50 Wl So Dak Owned R | 1981 | 5,147 | Good |
| SD050 over Vermillion Rv | 1981 | 5,147 | Fair |
| SD046 over Blind Ck | 2020 | 3,303 | Good |
| SD050 E over SD050 L | 1977 | 3,094 | Fair |
| SD019 over Vermillion Rv | 1997 | 2,764 | Good |
| SD019 over BNSF RR | 1997 | 2,764 | Good |
| SD046 over West Fork Frog Ck | 2021 | 2,559 | Good |
| SD046 over East Fork Frog Ck | 1983 | 2,559 | Fair |
| SD046 over Vermillion Rv | 2020 | 2,537 | Good |
| SD019 over Missouri River/county Rd | 2001 | 1,609 | Fair |
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.