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I-5 over Capitol Lake

Thurston County, Washington · rated Good in the 2025 National Bridge Inventory

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

I-5 over Capitol Lake in Thurston County, Washington, is rated in good condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
It was built in 1956 and reconstructed in 1986, making it 69 years old at the 2025 inventory.
It carries about 49,410 vehicles a day (traffic count year 2023).
Its listed owner is the state highway agency.
It is one of 118 of the 199 inventoried bridges in Thurston County rated good (59.3%); 2 (1.0%) are rated poor.
A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.

Component ratings


Structure	Continuous concrete multiple box beam
Length	about 392 ft
Location	0.5 N Jct US 101
NBI structure number	0005090A0000000
Condition class	Good

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

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