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Ia 4 over W. Fork Des Moines River

Palo Alto County, Iowa · rated Fair in the 2025 National Bridge Inventory

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

Ia 4 over W. Fork Des Moines River in Palo Alto County, Iowa, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the substructure, rated 5 (fair condition) on the 0-9 scale.
It was built in 1958, making it 67 years old at the 2025 inventory.
It carries about 2,460 vehicles a day (traffic count year 2022).
Its listed owner is the state highway agency.
It is one of 79 of the 135 inventoried bridges in Palo Alto County rated fair (58.5%); 21 (15.6%) 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 325 ft
Location	3.2 mi. S of S jct. US 18
NBI structure number	000000000039220
Condition class	Fair

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

Bridge	Built	Vehicles/day	Condition
US 18 & Ia 4 over W Fork Des Moines River	1965	4,890	Good
US 18 over Drainage Ditch	1958	3,500	Fair
US 18 over Cylinder Creek	2023	3,390	Good
US 18 over Prairie Creek	1923	2,510	Fair
Ia 4 over Drainage Ditch	1918	2,040	Fair
Ia 4 over Drainage Ditch #41	2000	2,040	Fair