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Irr US012 over Deep Bank Ck

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

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

Irr US012 over Deep Bank Ck in Corson 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 superstructure, rated 6 (satisfactory condition) on the 0-9 scale.
It was built in 1965, making it 60 years old at the 2025 inventory.
It carries about 1,091 vehicles a day (traffic count year 2024).
Its listed owner is the state highway agency.
It is one of 26 of the 49 inventoried bridges in Corson County rated fair (53.1%); 4 (8.2%) 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.

Component ratings


Structure	Continuous steel stringer or multi-beam girder
Length	about 182 ft
Location	6.6 NW Jct Sd 20
NBI structure number	000000016666216
Condition class	Fair

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

Bridge	Built	Vehicles/day	Condition
Irr US012 over Claymore Ck	1958	1,378	Poor
Irr US012 over Br Snake Ck	1965	1,091	Fair
Irr US012 over Snake Ck	1966	1,091	Fair
Irr SD020 over Ck	2000	956	Good
Irr SD063 over Oak Ck	1980	864	Fair
Irr SD063 over Ck	1980	864	Good