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FM over Dm River

Mahaska County, Iowa · rated Good in the 2025 National Bridge Inventory

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

FM over Dm River in Mahaska County, Iowa, is rated in good condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the substructure, rated 7 (good condition) on the 0-9 scale.
It was built in 2010, making it 15 years old at the 2025 inventory.
It carries about 620 vehicles a day (traffic count year 2022).
Its listed owner is the county highway agency.
It is one of 65 of the 221 inventoried bridges in Mahaska County rated good (29.4%); 67 (30.3%) are rated poor.
A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.

Component ratings


Structure	Continuous steel girder and floorbeam
Length	about 1,139 ft
Location	074160504
NBI structure number	000000000235631
Condition class	Good

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

Bridge	Built	Vehicles/day	Condition
US 63 over Nenebec Creek	1998	12,500	Fair
Ia 163 over Muchakinok Creek	1997	12,200	Fair
Ia 163 over Little Muchikinock Creek	1995	7,800	Fair
US 63 over Little Muchakinock Creek	1963	6,600	Fair
Ia 92 over Spring Creek/pedestrian	1958	6,400	Fair
US 63 over Stream	1982	6,350	Good