US Bridges

I 90 over St. Regis Rvr-Local RD

Fair

Mineral County, Montana · 4.3M E De Borgia · Structure no. I00090023+00631

Built
1979
46 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
455 ft
3 main spans
Daily traffic
7,448
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over St. Regis Rvr-Local RD is a steel continuous stringer/multi-beam or girder carrying I 90 over St. Regis Rvr-Local RD in Mineral County, Montana. It was built in 1979, so it is 46 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 7,448 vehicles a day, roughly 26% of them trucks, projected to reach 7,820 by 2043. The structure is 455 ft (138.7 m) long and 88 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesI 90
CrossesSt. Regis Rvr-Local RD
Location4.3M E De Borgia
RouteInterstate 90
CountyMineral County
StateMontana
Coordinates47.34437, -115.28024
Functional classRural 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry9: Superior to present desirable criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating23 US tons
Inventory rating18 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length455 ft (138.7 m)
Longest span175 ft (53.3 m)
Deck width88 ft (26.9 m)
Roadway width86 ft (26.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,448 (2023)
Projected traffic7,820 by 2043
Trucks26%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesHighway and waterway
Detour if closed1.9 mi (3 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was I 90 over St. Regis Rvr-Local RD built?

It was built in 1979, making it 46 years old in 2025.

What condition is I 90 over St. Regis Rvr-Local RD 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 July 2023.

How much traffic does I 90 over St. Regis Rvr-Local RD carry?

About 7,448 vehicles per day (2023 count), of which roughly 26% are trucks.

How long is I 90 over St. Regis Rvr-Local RD?

The structure is 455 ft (138.7 m) long with a longest span of 175 ft (53.3 m) and a deck 88 ft wide.

Who owns I 90 over St. Regis Rvr-Local RD?

It is owned by the State Highway Agency.