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Forest Road 320 over South Fork Noyo River

Mendocino County, California · rated Fair in the 2025 National Bridge Inventory

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

Forest Road 320 over South Fork Noyo River in Mendocino County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
It was built in 1948, making it 77 years old at the 2025 inventory.
It carries about 125 vehicles a day (traffic count year 2009).
It is one of 205 of the 356 inventoried bridges in Mendocino County rated fair (57.6%); 27 (7.6%) 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	Timber stringer or multi-beam girder
Length	about 63 ft
Location	Parlin Fork Conservation
NBI structure number	10F0011
Condition class	Fair

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

Bridge	Built	Vehicles/day	Condition
State Route 1 over Pudding Creek	1959	23,950	Good
State Route 001 over Noyo River & Harbor Dr	2005	23,950	Good
U.S. Highway 101 over Austin Creek	1964	20,900	Good
North State St over Forsythe Creek	1949	20,200	Fair
U.S. Highway 101 over Ncrra/nwp RR	1957	19,000	Fair
U.S. Highway 101 over Baker Creek	1971	19,000	Good