US Bridges

US 87 over Cottonwood Creek

Fair

Fergus County, Montana · 5M SW Lewistown · Structure no. P00057075+05591

Built
2009
16 years old
Condition
Fair
inspected May 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
132 ft
1 main span
Daily traffic
2,589
2023 count
Owner
State
State Highway Agency

About this bridge

US 87 over Cottonwood Creek is a prestressed concrete stringer/multi-beam or girder carrying US 87 over Cottonwood Creek in Fergus County, Montana. It was built in 2009, so it is 16 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 2,589 vehicles a day, roughly 6% of them trucks, projected to reach 2,718 by 2043. The structure is 132 ft (40.3 m) long and 39 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesUS 87
CrossesCottonwood Creek
Location5M SW Lewistown
RouteU.S. Route 87
CountyFergus County
StateMontana
Coordinates47.05301, -109.55902
Functional classRural Principal Arterial - Other

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 inspectionMay 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating55 US tons
Inventory rating34 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length132 ft (40.3 m)
Longest span102 ft (31 m)
Deck width39 ft (12 m)
Roadway width39 ft (12 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,589 (2023)
Projected traffic2,718 by 2043
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemYes

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 US 87 over Cottonwood Creek built?

It was built in 2009, making it 16 years old in 2025.

What condition is US 87 over Cottonwood 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 May 2023.

How much traffic does US 87 over Cottonwood Creek carry?

About 2,589 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is US 87 over Cottonwood Creek?

The structure is 132 ft (40.3 m) long with a longest span of 102 ft (31 m) and a deck 39 ft wide.

Who owns US 87 over Cottonwood Creek?

It is owned by the State Highway Agency.