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180TH Street over Trib. to Big Sioux River

Hamlin County, South Dakota · rated Poor in the 2025 National Bridge Inventory

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

180TH Street over Trib. to Big Sioux River in Hamlin County, South Dakota, is rated in poor condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the culvert, rated 3 (serious condition) on the 0-9 scale.
It was built in 1930, making it 95 years old at the 2025 inventory.
It carries about 25 vehicles a day (traffic count year 2022).
Its listed owner is the county highway agency.
It is one of 7 of the 61 inventoried bridges in Hamlin County rated poor (11.5%); 7 (11.5%) are rated poor.
A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.

Component ratings

Component	Rating (2025)	FHWA scale meaning
Culvert	3	Serious condition


Structure	Continuous concrete culvert
Length	about 21 ft
Location	3N & 0.9W of Castlewood
NBI structure number	000000029221020
Condition class	Poor

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

Bridge	Built	Vehicles/day	Condition
I029 S over 462 Ave	1973	4,595	Fair
I029 N over 462 Ave	1973	4,595	Fair
I029 S over Stray Horse Ck	1973	4,595	Fair
I029 N over Stray Horse Ck	1973	4,595	Fair
I029 S over SD022	1973	4,595	Fair
I029 N over SD022	1973	4,595	Fair