US Bridges

IRR - S 39 over Sheep Creek

Fair

Rosebud County, Montana · 16M NW Colstrip · Structure no. P00039038+06861

Built
1982
43 years old
Condition
Fair
inspected February 2025
Type
Culvert
Steel
Length
46 ft
3 main spans
Daily traffic
787
2023 count
Owner
State
State Highway Agency

About this bridge

IRR - S 39 over Sheep Creek is a steel culvert carrying IRR - S 39 over Sheep Creek in Rosebud County, Montana. It was built in 1982, so it is 43 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 787 vehicles a day, roughly 8% of them trucks, projected to reach 826 by 2043. The structure is 46 ft (14.1 m) long. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesIRR - S 39
CrossesSheep Creek
Location16M NW Colstrip
RouteState Highway 39
CountyRosebud County
StateMontana
Coordinates46.08806, -106.74397
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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating84.7 US tons
Inventory rating82.9 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans3
Design loadHS 20
Structure length46 ft (14.1 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic787 (2023)
Projected traffic826 by 2043
Trucks8%
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 IRR - S 39 over Sheep Creek built?

It was built in 1982, making it 43 years old in 2025.

What condition is IRR - S 39 over Sheep 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 February 2025.

How much traffic does IRR - S 39 over Sheep Creek carry?

About 787 vehicles per day (2023 count), of which roughly 8% are trucks.

How long is IRR - S 39 over Sheep Creek?

The structure is 46 ft (14.1 m) long with a longest span of 10 ft (3 m).

Who owns IRR - S 39 over Sheep Creek?

It is owned by the State Highway Agency.