US Bridges

US101 (hwy 9) over Mill Creek

Fair

Clatsop County, Oregon · 002 MI N Seaside · Structure no. 03079A009 01958

Built
1957
68 years old
Condition
Fair
inspected October 2023
Type
Culvert
Steel Continuous
Length
20 ft
3 main spans
Daily traffic
16,489
2022 count
Owner
State
State Highway Agency

About this bridge

US101 (hwy 9) over Mill Creek is a steel continuous culvert carrying US101 (hwy 9) over Mill Creek in Clatsop County, Oregon. It was built in 1957, so it is 68 years old, older than the Oregon average of 49.9 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 16,489 vehicles a day, roughly 4% of them trucks, projected to reach 16,600 by 2042. The structure is 20 ft (6.1 m) long. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesUS101 (hwy 9)
CrossesMill Creek
Location002 MI N Seaside
RouteU.S. Route 101
CountyClatsop County
StateOregon
Coordinates46.01287, -123.91086
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Culvert5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating98.9 US tons
Inventory rating76.1 US tons

Structure

Structure typeCulvert
MaterialSteel Continuous
DeckNot applicable
Main spans3
Design loadHS 20
Structure length20 ft (6.1 m)
Longest span6 ft (1.8 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic16,489 (2022)
Projected traffic16,600 by 2042
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US101 (hwy 9) over Mill Creek built?

It was built in 1957, making it 68 years old in 2025.

What condition is US101 (hwy 9) over Mill Creek in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in October 2023.

How much traffic does US101 (hwy 9) over Mill Creek carry?

About 16,489 vehicles per day (2022 count), of which roughly 4% are trucks.

How long is US101 (hwy 9) over Mill Creek?

The structure is 20 ft (6.1 m) long with a longest span of 6 ft (1.8 m).

Who owns US101 (hwy 9) over Mill Creek?

It is owned by the State Highway Agency.