Bridge conditions in Sanborn County, South Dakota
54 inventoried bridges · 7 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
Sanborn County has 7 bridges rated poor out of 54 inventoried, a 13.0% share that puts it well above the national rate of about 7%.
- 7 of the 54 bridges in Sanborn County, South Dakota, are rated in poor condition (13.0%) in the 2025 National Bridge Inventory, as of .
- 18 bridges (33.3%) are rated good and 29 (53.7%) fair.
- The median Sanborn County bridge was built in 1977.
- The busiest poor-rated bridge is 397TH Ave. over Morris Ck (built 1930), carrying about 225 vehicles a day.
Good 33.3% · Fair 53.7% · Poor 13.0% of 54 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 |
|---|---|---|---|
| 397TH Ave. over Morris Ck | 1930 | 225 | Poor |
| 414TH Ave. over Jim Ck | 1930 | 120 | Poor |
| County Rd over Sand Ck | 1940 | 70 | Poor |
| 220 St. over Ck | 1920 | 56 | Poor |
| 416TH Ave. over Ck | 1920 | 56 | Poor |
| 397TH Ave. over Sand Ck | 1920 | 35 | Poor |
| 241 St over James Rv | 1973 | 16 | Poor |
Busiest bridges in the county
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| SD034 over Drainage Ditch | 1936 | 1,738 | Fair |
| SD034 W over James Rv | 2003 | 1,484 | Fair |
| SD034 E over James Rv | 2004 | 1,484 | Fair |
| SD037 S over Sand Ck | 1977 | 1,354 | Good |
| SD037 N over Sand Ck | 1976 | 1,354 | Good |
| SD037 S over James Rv | 2002 | 1,271 | Good |
| SD037 N over James Rv | 1992 | 1,271 | Good |
| SD224 over Dry Run Ck | 1962 | 1,118 | Fair |
| 241ST Street over Morris Ck | 1930 | 253 | Fair |
| 397TH Ave. over Morris Ck | 1930 | 225 | Poor |
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.