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M 4 over Willow River

Pine County, Minnesota · rated Poor in the 2025 National Bridge Inventory

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

M 4 over Willow River in Pine County, Minnesota, is rated in poor condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the substructure, rated 4 (poor condition) on the 0-9 scale.
It was built in 1924, making it 101 years old at the 2025 inventory.
It carries about 80 vehicles a day (traffic count year 2001).
Its listed owner is a city or municipal highway agency.
It is one of 7 of the 172 inventoried bridges in Pine County rated poor (4.1%); 7 (4.1%) 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


Structure	Concrete girder and floorbeam
Length	about 32 ft
Location	0.3 Mi N of Jct Csah 61
NBI structure number	2683
Condition class	Poor

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

Bridge	Built	Vehicles/day	Condition
I 35 over St Croix Valley RR	2016	11,998	Good
I 35 over St Croix Valley RR	2016	11,998	Good
I 35 over Snake River	2018	10,450	Good
I 35 over Snake River	2018	10,450	Good
I 35 over Mission Creek	1964	8,848	Fair
I 35 over Mission Creek	1964	8,848	Good