US Bridges

I 15 over Missouri Rvr-Rr-Local

Fair

Lewis and Clark County, Montana · 5M N Craig · Structure no. I00015239+01771

Built
1971
54 years old
Condition
Fair
inspected June 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
1,250 ft
4 main spans
Daily traffic
2,201
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 over Missouri Rvr-Rr-Local is a steel continuous stringer/multi-beam or girder carrying I 15 over Missouri Rvr-Rr-Local in Lewis and Clark County, Montana. It was built in 1971, so it is 54 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 2,201 vehicles a day, roughly 16% of them trucks, projected to reach 2,343 by 2043. The structure is 1,250 ft (380.9 m) long and 41 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 15
CrossesMissouri Rvr-Rr-Local
Location5M N Craig
RouteInterstate 15
CountyLewis and Clark County
StateMontana
Coordinates47.12809, -111.91119
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 protection7 GoodSome minor problems.
Last inspectionJune 2024
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 geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating29.3 US tons
Inventory rating22.5 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans4 (+6 approach)
Design loadHS 20
Structure length1,250 ft (380.9 m)
Longest span185 ft (56.4 m)
Deck width41 ft (12.4 m)
Roadway width38 ft (11.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,201 (2023)
Projected traffic2,343 by 2043
Trucks16%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway, waterway and railroad
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was I 15 over Missouri Rvr-Rr-Local built?

It was built in 1971, making it 54 years old in 2025.

What condition is I 15 over Missouri Rvr-Rr-Local 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 2024.

How much traffic does I 15 over Missouri Rvr-Rr-Local carry?

About 2,201 vehicles per day (2023 count), of which roughly 16% are trucks.

How long is I 15 over Missouri Rvr-Rr-Local?

The structure is 1,250 ft (380.9 m) long with a longest span of 185 ft (56.4 m) and a deck 41 ft wide.

Who owns I 15 over Missouri Rvr-Rr-Local?

It is owned by the State Highway Agency.