US Bridges

US 89 over Shields River

Fair

Park County, Montana · 1M N Clyde Park · Structure no. P00059016+06481

Built
1981
44 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
153 ft
2 main spans
Daily traffic
1,271
2023 count
Owner
State
State Highway Agency

About this bridge

US 89 over Shields River is a prestressed concrete stringer/multi-beam or girder carrying US 89 over Shields River in Park County, Montana. It was built in 1981, so it is 44 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 1,271 vehicles a day, roughly 4% of them trucks, projected to reach 1,335 by 2043. The structure is 153 ft (46.5 m) long and 46 ft wide. If it were closed, the detour would be 88.2 mi (142 km).

Location

Open in Google Maps
CarriesUS 89
CrossesShields River
Location1M N Clyde Park
RouteU.S. Route 89
CountyPark County
StateMontana
Coordinates45.9047, -110.61168
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52 US tons
Inventory rating27 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length153 ft (46.5 m)
Longest span75 ft (22.9 m)
Deck width46 ft (14.1 m)
Roadway width43 ft (13.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,271 (2023)
Projected traffic1,335 by 2043
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed88.2 mi (142 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 US 89 over Shields River built?

It was built in 1981, making it 44 years old in 2025.

What condition is US 89 over Shields 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 US 89 over Shields River carry?

About 1,271 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is US 89 over Shields River?

The structure is 153 ft (46.5 m) long with a longest span of 75 ft (22.9 m) and a deck 46 ft wide.

Who owns US 89 over Shields River?

It is owned by the State Highway Agency.