US Bridges

I 94 over Tongue River

Fair

Custer County, Montana · 1M S Miles City · Structure no. I00094137+04601

Built
1961
64 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
294 ft
3 main spans
Daily traffic
4,707
2023 count
Owner
State
State Highway Agency

About this bridge

I 94 over Tongue River is a steel continuous stringer/multi-beam or girder carrying I 94 over Tongue River in Custer County, Montana. It was built in 1961, so it is 64 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 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 4,707 vehicles a day, roughly 23% of them trucks, projected to reach 4,942 by 2043. The structure is 294 ft (89.6 m) long and 32 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 94
CrossesTongue River
Location1M S Miles City
RouteInterstate 94
CountyCuster County
StateMontana
Coordinates46.38473, -105.84546
Functional classUrban Principal Arterial - Interstate

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourCountermeasures installed to correct a previously existing problem
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36.4 US tons
Inventory rating28.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length294 ft (89.6 m)
Longest span112 ft (34.1 m)
Deck width32 ft (9.7 m)
Roadway width28 ft (8.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,707 (2023)
Projected traffic4,942 by 2043
Trucks23%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$821,000
NavigationNo navigation control on waterway

Frequently asked questions

When was I 94 over Tongue River built?

It was built in 1961, making it 64 years old in 2025.

What condition is I 94 over Tongue 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 June 2023.

How much traffic does I 94 over Tongue River carry?

About 4,707 vehicles per day (2023 count), of which roughly 23% are trucks.

How long is I 94 over Tongue River?

The structure is 294 ft (89.6 m) long with a longest span of 112 ft (34.1 m) and a deck 32 ft wide.

Who owns I 94 over Tongue River?

It is owned by the State Highway Agency.