US Bridges

US 89 over Big Creek

Fair

Park County, Montana · 7M SW Emigrant · Structure no. P00011024+00721

Built
1960
65 years old
Condition
Fair
inspected August 2023
Type
Tee Beam
Concrete Continuous
Length
90 ft
3 main spans
Daily traffic
2,289
2023 count
Owner
State
State Highway Agency

About this bridge

US 89 over Big Creek is a concrete continuous tee beam carrying US 89 over Big Creek in Park County, Montana. It was built in 1960, so it is 65 years old, older 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 2,289 vehicles a day, roughly 3% of them trucks, projected to reach 2,426 by 2043. The structure is 90 ft (27.4 m) long and 32 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesUS 89
CrossesBig Creek
Location7M SW Emigrant
RouteU.S. Route 89
CountyPark County
StateMontana
Coordinates45.29921, -110.83145
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating31 US tons
Inventory rating21.1 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length90 ft (27.4 m)
Longest span54 ft (16.5 m)
Deck width32 ft (9.8 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,289 (2023)
Projected traffic2,426 by 2043
Trucks3%
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 89 over Big Creek built?

It was built in 1960, making it 65 years old in 2025.

What condition is US 89 over Big 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 August 2023.

How much traffic does US 89 over Big Creek carry?

About 2,289 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is US 89 over Big Creek?

The structure is 90 ft (27.4 m) long with a longest span of 54 ft (16.5 m) and a deck 32 ft wide.

Who owns US 89 over Big Creek?

It is owned by the State Highway Agency.