US Bridges

S 72 over Clarks Fork Yellowstone

Fair

Carbon County, Montana · 4M NE Belfry · Structure no. P00072014+04031

Built
2011
14 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
280 ft
3 main spans
Daily traffic
1,732
2023 count
Owner
State
State Highway Agency

About this bridge

S 72 over Clarks Fork Yellowstone is a prestressed concrete stringer/multi-beam or girder carrying S 72 over Clarks Fork Yellowstone in Carbon County, Montana. It was built in 2011, so it is 14 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 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 1,732 vehicles a day, roughly 9% of them trucks, projected to reach 1,819 by 2043. The structure is 280 ft (85.3 m) long and 45 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesS 72
CrossesClarks Fork Yellowstone
Location4M NE Belfry
RouteState Highway 72
CountyCarbon County
StateMontana
Coordinates45.18976, -108.98442
Functional classRural Minor 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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionNovember 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
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating56 US tons
Inventory rating28 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length280 ft (85.3 m)
Longest span90 ft (27.4 m)
Deck width45 ft (13.8 m)
Roadway width42 ft (12.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,732 (2023)
Projected traffic1,819 by 2043
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

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 S 72 over Clarks Fork Yellowstone built?

It was built in 2011, making it 14 years old in 2025.

What condition is S 72 over Clarks Fork Yellowstone 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 S 72 over Clarks Fork Yellowstone carry?

About 1,732 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is S 72 over Clarks Fork Yellowstone?

The structure is 280 ft (85.3 m) long with a longest span of 90 ft (27.4 m) and a deck 45 ft wide.

Who owns S 72 over Clarks Fork Yellowstone?

It is owned by the State Highway Agency.