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Bridge conditions in Mason County, Washington

136 inventoried bridges · 4 rated poor · 2025 National Bridge Inventory

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

4 of the 136 bridges the federal inventory lists in Mason County are rated poor; the rest split 77 good and 55 fair.

4 of the 136 bridges in Mason County, Washington, are rated in poor condition (2.9%) in the 2025 National Bridge Inventory, as of August 20, 2026.
77 bridges (56.6%) are rated good and 55 (40.4%) fair.
The median Mason County bridge was built in 1972.
The busiest poor-rated bridge is US 101 over Matlock Rd (built 1973), carrying about 18,182 vehicles a day.

Good 56.6% · Fair 40.4% · Poor 2.9% of 136 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 101 over Matlock Rd	1973	18,182	Poor
Agate Loop Rd over Campbell Creek	1950	257	Poor
W. Bulb Farm Rd. over Cloquallum Creek	1961	62	Poor
No Data Entered over Lena Creek	1964	25	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
US 101 over Mill Creek	1973	19,397	Good
US 101 over Creek/rr/street	1973	18,182	Fair
US 101 over Matlock Rd	1973	18,182	Poor
SR 3 over Goldsborough Creek	1923	17,285	Fair
US 101 over SR 3	1972	17,050	Fair
SR 3 over Deer Creek	1957	15,878	Good
SR 3 over Cranberry Creek	1957	15,815	Fair
SR 3 over Johns Creek	1948	15,751	Fair
SR 3 over Mill Creek	1921	15,354	Fair
US 101 over Kennedy Creek	1960	13,297	Fair

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

All of Washington: Washington 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.