US Bridges

1-LANE Road over W.Fork Stillwater River

Fair

Sweet Grass County, Montana · No Data Entered · Structure no. 010802000001001

Built
1964
61 years old
Condition
Fair
inspected September 2023
Type
Girder and Floorbeam System
Wood or Timber
Length
40 ft
1 main span
Daily traffic
50
Owner
Federal
U.S. Forest Service

About this bridge

1-LANE Road over W.Fork Stillwater River is a wood or timber girder and floorbeam system carrying 1-LANE Road over W.Fork Stillwater River in Sweet Grass County, Montana. It was built in 1964, so it is 61 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 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 50 vehicles a day, projected to reach 75 by 2045. The structure is 40 ft (12.2 m) long and 16 ft wide.

Location

Open in Google Maps
Carries1-LANE Road
CrossesW.Fork Stillwater River
LocationNo Data Entered
RouteFederal Lands Road 2846
CountySweet Grass County
StateMontana
Coordinates45.39763, -109.96729
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating37.1 US tons
Inventory rating28.5 US tons

Structure

Structure typeGirder and Floorbeam System
MaterialWood or Timber
DeckWood or timber
Main spans1 (+1 approach)
Design loadHS 20
Structure length40 ft (12.2 m)
Longest span39 ft (11.9 m)
Deck width16 ft (4.9 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (—)
Projected traffic75 by 2045
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerU.S. Forest Service
Maintained byU.S. Forest Service
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was 1-LANE Road over W.Fork Stillwater River built?

It was built in 1964, making it 61 years old in 2025.

What condition is 1-LANE Road over W.Fork Stillwater River 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 September 2023.

How much traffic does 1-LANE Road over W.Fork Stillwater River carry?

About 50 vehicles per day (latest count).

How long is 1-LANE Road over W.Fork Stillwater River?

The structure is 40 ft (12.2 m) long with a longest span of 39 ft (11.9 m) and a deck 16 ft wide.

Who owns 1-LANE Road over W.Fork Stillwater River?

It is owned by the U.S. Forest Service.