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M-32 over S Br Thunder Bay River

Alpena County, Michigan · rated Good in the 2025 National Bridge Inventory

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

M-32 over S Br Thunder Bay River in Alpena County, Michigan, is rated in good condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the superstructure, rated 7 (good condition) on the 0-9 scale.
It was built in 1932 and reconstructed in 2009, making it 93 years old at the 2025 inventory.
It carries about 4,144 vehicles a day (traffic count year 2006).
Its listed owner is the state highway agency.
It is one of 11 of the 32 inventoried bridges in Alpena County rated good (34.4%); 2 (6.2%) 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	Prestressed concrete stringer or multi-beam girder
Length	about 49 ft
Location	4.7 Mi E Montmorency Col
NBI structure number	000000000000328
Condition class	Good

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

Bridge	Built	Vehicles/day	Condition
US-23 over Thunder Bay River	1932	16,200	Fair
Second Avenue over Thunder Bay River	1939	15,700	Fair
Bagley Street over Thunder Bay River	2021	15,000	Good
US-23 over S Br Devil River	1936	5,537	Fair
US-23 over N Br Devil River	1933	5,537	Fair
M-32 over Bean Creek	1934	5,505	Fair