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Bridge conditions in Thurston County, Washington

199 inventoried bridges · 2 rated poor · 2025 National Bridge Inventory

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

Thurston County tracks close to typical: 2 of its 199 inventoried bridges (1.0%) are rated poor, against a national rate of about 7%.

2 of the 199 bridges in Thurston County, Washington, are rated in poor condition (1.0%) in the 2025 National Bridge Inventory, as of August 20, 2026.
118 bridges (59.3%) are rated good and 79 (39.7%) fair.
The median Thurston County bridge was built in 1982.
The busiest poor-rated bridge is Capitol Blvd over I-5 Ramp (built 1956), carrying about 13,767 vehicles a day.

Good 59.3% · Fair 39.7% · Poor 1.0% of 199 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
Capitol Blvd over I-5 Ramp	1956	13,767	Poor
Plum-n Ramp over Eastside St SE	1957	6,876	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
I-5 over Owr N RR	1957	69,477	Fair
I-5 over Henderson Blvd	1957	69,477	Good
I-5 over Nisqually River	1937	62,815	Fair
I-5 over Nisqually River	1967	62,815	Fair
US 101 NB over I-5 Ramps Street	1990	62,306	Good
I-5 over Pacific Ave	1957	59,814	Fair
I-5 over Linwood Ave	1955	51,489	Good
I-5 over Mcallister CR	1968	50,433	Fair
I-5 over Mcallister Creek	1968	50,433	Fair
I-5 over Nisqually Overflow	1968	50,433	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.