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Tyndall Road over Big Sable River

Mason County, Michigan · rated Poor in the 2025 National Bridge Inventory

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

Tyndall Road over Big Sable River in Mason County, Michigan, is rated in poor condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the superstructure, rated 4 (poor condition) on the 0-9 scale.
It was built in 1900 and reconstructed in 1974, making it 125 years old at the 2025 inventory.
It carries about 200 vehicles a day (traffic count year 1997).
Its listed owner is the county highway agency.
It is one of 4 of the 66 inventoried bridges in Mason County rated poor (6.1%); 4 (6.1%) 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	Steel stringer or multi-beam girder
Length	about 30 ft
Location	7 Mi E of Fountain
NBI structure number	000000000006679
Condition class	Poor

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

Bridge	Built	Vehicles/day	Condition
Old US-31 over CSX RR	1935	11,200	Good
Old US-31 over Durham Creek	1925	8,600	Fair
Old US-31 over Pere Marquette River	1925	7,076	Fair
Old US-31 over Pere Marquette River	1924	6,828	Fair
US-31 over S Br Lincoln River	1992	6,578	Fair
US-31 over N Br Lincoln River	1992	6,578	Fair