US Bridges

Panisco Road over Mill Creek

Good

Lewis County, Washington · 9.0 E Onalaska · Structure no. 081690000000000

Built
1973
52 years old
Condition
Good
inspected January 2024
Type
Slab
Concrete
Length
40 ft
1 main span
Daily traffic
45
2021 count
Owner
County
County Highway Agency

About this bridge

Panisco Road over Mill Creek is a concrete slab carrying Panisco Road over Mill Creek in Lewis County, Washington. It was built in 1973, so it is 52 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 45 vehicles a day, roughly 33% of them trucks, projected to reach 82 by 2041. The structure is 40 ft (12.2 m) long and 26 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

CarriesPanisco Road
CrossesMill Creek
Location9.0 E Onalaska
RouteCounty Highway 66570
Coordinates46.60964, -122.53174
Functional classRural Local

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJanuary 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36 US tons
Inventory rating20.9 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length40 ft (12.2 m)
Longest span28 ft (8.5 m)
Deck width26 ft (7.9 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic45 (2021)
Projected traffic82 by 2041
Trucks33%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedOther structural work, including hydraulic replacements
Estimated improvement cost$437,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Panisco Road over Mill Creek built?

It was built in 1973, making it 52 years old in 2025.

What condition is Panisco Road over Mill Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in January 2024.

How much traffic does Panisco Road over Mill Creek carry?

About 45 vehicles per day (2021 count), of which roughly 33% are trucks.

How long is Panisco Road over Mill Creek?

The structure is 40 ft (12.2 m) long with a longest span of 28 ft (8.5 m) and a deck 26 ft wide.

Who owns Panisco Road over Mill Creek?

It is owned by the County Highway Agency.