US Bridges

Birdland Bay RD over Clark Fork River 001

Fair

Sanders County, Montana · 2M W Thompson Falls · Structure no. L45298000+03001

Built
1928
97 years old
Condition
Fair
inspected July 2024
Type
Truss - Thru
Steel
Length
310 ft
1 main span
Daily traffic
100
2025 count
Owner
County
County Highway Agency

About this bridge

Birdland Bay RD over Clark Fork River 001 is a steel truss - thru carrying Birdland Bay RD over Clark Fork River 001 in Sanders County, Montana. It was built in 1928, so it is 97 years old, older 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 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 100 vehicles a day, roughly 3% of them trucks, projected to reach 100 by 2040. The structure is 310 ft (94.5 m) long and 21 ft wide. If it were closed, the detour would be 44.7 mi (72 km).

Location

Open in Google Maps
CarriesBirdland Bay RD
CrossesClark Fork River 001
Location2M W Thompson Falls
RouteCounty Highway 45066
CountySanders County
StateMontana
Coordinates47.62152, -115.39159
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2024
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
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating54 US tons
Inventory rating32 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckConcrete, cast-in-place
Main spans1 (+1 approach)
Design loadH 15
Structure length310 ft (94.5 m)
Longest span275 ft (83.8 m)
Deck width21 ft (6.5 m)
Roadway width20 ft (6.2 m)
Vertical clearance over deck11 ft (3.3 m)

Traffic and service

Average daily traffic100 (2025)
Projected traffic100 by 2040
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed44.7 mi (72 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$558,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Birdland Bay RD over Clark Fork River 001 built?

It was built in 1928, making it 97 years old in 2025.

What condition is Birdland Bay RD over Clark Fork River 001 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 July 2024.

How much traffic does Birdland Bay RD over Clark Fork River 001 carry?

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

How long is Birdland Bay RD over Clark Fork River 001?

The structure is 310 ft (94.5 m) long with a longest span of 275 ft (83.8 m) and a deck 21 ft wide.

Who owns Birdland Bay RD over Clark Fork River 001?

It is owned by the County Highway Agency.