24510 420 Avenue over Rock Ck

Hanson County, South Dakota · rated Fair in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

• 24510 420 Avenue over Rock Ck in Hanson County, South Dakota, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
• Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
• It was built in 1984, making it 41 years old at the 2025 inventory.
• It carries about 60 vehicles a day (traffic count year 2022).
• Its listed owner is the county highway agency.
• It is one of 42 of the 62 inventoried bridges in Hanson County rated fair (67.7%); 8 (12.9%) are rated poor.
• A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.

View this bridge on a map → (43.83224, -97.80817)

Component ratings

Bridge details

Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.

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Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.