US Bridges

Swan River RD over Swan River 008

Fair

Flathead County, Montana · 1M W Ferndale · Structure no. L15657002+06001

Built
1998
27 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
291 ft
4 main spans
Daily traffic
100
2025 count
Owner
County
County Highway Agency

About this bridge

Swan River RD over Swan River 008 is a prestressed concrete stringer/multi-beam or girder carrying Swan River RD over Swan River 008 in Flathead County, Montana. It was built in 1998, so it is 27 years old, younger than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 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 100 vehicles a day, roughly 3% of them trucks, projected to reach 100 by 2040. The structure is 291 ft (88.7 m) long and 31 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

CarriesSwan River RD
CrossesSwan River 008
Location1M W Ferndale
RouteCounty Highway 15657
StateMontana
Coordinates48.05569, -114.02967
Functional classRural Local

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating50 US tons
Inventory rating35.1 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length291 ft (88.7 m)
Longest span73 ft (22.4 m)
Deck width31 ft (9.6 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic100 (2025)
Projected traffic100 by 2040
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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 Swan River RD over Swan River 008 built?

It was built in 1998, making it 27 years old in 2025.

What condition is Swan River RD over Swan River 008 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 November 2023.

How much traffic does Swan River RD over Swan River 008 carry?

About 100 vehicles per day (2025 count), of which roughly 3% are trucks.

How long is Swan River RD over Swan River 008?

The structure is 291 ft (88.7 m) long with a longest span of 73 ft (22.4 m) and a deck 31 ft wide.

Who owns Swan River RD over Swan River 008?

It is owned by the County Highway Agency.