US Bridges

IRR - S 251 over Kirn Coulee

Good

Roosevelt County, Montana · 22M NE Poplar · Structure no. S00251017+08001

Built
2008
17 years old
Condition
Good
inspected November 2023
Type
Culvert
Steel
Length
30 ft
2 main spans
Daily traffic
88
2023 count
Owner
State
State Highway Agency

About this bridge

IRR - S 251 over Kirn Coulee is a steel culvert carrying IRR - S 251 over Kirn Coulee in Roosevelt County, Montana. It was built in 2008, so it is 17 years old, younger than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 88 vehicles a day, roughly 18% of them trucks, projected to reach 92 by 2043. The structure is 30 ft (9.1 m) long. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesIRR - S 251
CrossesKirn Coulee
Location22M NE Poplar
RouteState Highway 251
CountyRoosevelt County
StateMontana
Coordinates48.36133, -105.08333
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Channel and channel protection7 GoodSome minor problems.
Culvert7 GoodSome minor problems.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating110.1 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans2
Design loadH 15
Structure length30 ft (9.1 m)
Longest span13 ft (3.9 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic88 (2023)
Projected traffic92 by 2043
Trucks18%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.9 mi (24 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 251 over Kirn Coulee built?

It was built in 2008, making it 17 years old in 2025.

What condition is IRR - S 251 over Kirn Coulee in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in November 2023.

How much traffic does IRR - S 251 over Kirn Coulee carry?

About 88 vehicles per day (2023 count), of which roughly 18% are trucks.

How long is IRR - S 251 over Kirn Coulee?

The structure is 30 ft (9.1 m) long with a longest span of 13 ft (3.9 m).

Who owns IRR - S 251 over Kirn Coulee?

It is owned by the State Highway Agency.