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Bridge conditions in Humboldt County, California

399 inventoried bridges · 21 rated poor · 2025 National Bridge Inventory

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

The federal inventory lists 399 bridges in Humboldt County: 169 rated good, 209 fair, and 21 poor.

21 of the 399 bridges in Humboldt County, California, are rated in poor condition (5.3%) in the 2025 National Bridge Inventory, as of August 20, 2026.
169 bridges (42.4%) are rated good and 209 (52.4%) fair.
The median Humboldt County bridge was built in 1965.
The busiest poor-rated bridge is US Highway 101 NB over West End Rd Creek Ncrra (built 1929), carrying about 17,500 vehicles a day.

Good 42.4% · Fair 52.4% · Poor 5.3% of 399 bridges

Bridges rated poor

Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.

Bridge	Built	Vehicles/day	Condition
US Highway 101 NB over West End Rd Creek Ncrra	1929	17,500	Poor
U.S. Highway 101 over Dean Crk Rd & Dean Creek	1967	5,000	Poor
State Route 299 over Mad River	1965	4,775	Poor
Humboldt Hill Road over US Highway 101	1963	3,100	Poor
State Park Road over South Fork Eel River	1969	1,100	Poor
Maple Creek Road over North Fork Mad River	1928	624	Poor
Hookton Road over Salmon Creek	1922	486	Poor
Bald Hills Road over Prairie Creek	1957	479	Poor
Mattole Rd over Mattole River	1958	412	Poor
Alderpoint Rd over South Dobbyn Creek	1937	281	Poor
Salmon Creek Road over Salmon Creek	1959	226	Poor
Holmes Flat Road over Larabee Low Level-eel Ri	1960	100	Poor
Zenia Bluff Rd over South Dobbyn Creek	1949	85	Poor
Lindley Road over Mattole River	1925	50	Poor
33007: Butte Creek over Butte Creek	1980	50	Poor
No Data Entered over No Data Entered	1980	50	Poor
No Data Entered over No Data Entered	1981	50	Poor
Maple Creek Rd over Maple Creek	1955	38	Poor
Kneeland Rd over North Fork Yager Creek	1964	10	Poor
Albee Ck Camp over Albee Creek	1986	10	Poor
Grasshopper Lkt Rd over Squaw Creek	1983	1	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
U.S. Highway 101 over Orchard Ave	1963	25,700	Good
US Highway 101 SB over Palmer Blvd	1958	22,000	Fair
US Highway 101 NB over Palmer Blvd	1958	22,000	Fair
U.S. Highway 101 over US 101 On&off Ramp Ncrra	1962	21,700	Fair
U.S. Highway 101 over Salmon Creek	1957	21,500	Good
U.S. Highway 101 over Finch Creek Road	1958	21,500	Good
U.S. Highway 101 over Finch Creek Road	1958	21,500	Good
US Highway 101 over State Route 211	1957	20,400	Fair
US Highway 101 SB over Mad River	2011	18,500	Good
US Highway 101 NB over Jacoby Creek	1955	18,125	Good

Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.

Every bridge in Humboldt County → - all 399, busiest first, each with its own condition record.

All of California: California bridge conditions by county · every download on the data page.

Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.