US Bridges

Upper N Fork RD over N Fk Big Hole River 063

FairPosted for load

Beaverhead County, Montana · 6M NW Wisdom · Structure no. L01004006+09001

Built
1978
47 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
41 ft
1 main span
Daily traffic
100
2025 count
Owner
County
County Highway Agency

About this bridge

Upper N Fork RD over N Fk Big Hole River 063 is a steel stringer/multi-beam or girder carrying Upper N Fork RD over N Fk Big Hole River 063 in Beaverhead County, Montana. It was built in 1978, so it is 47 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. Its operating status is: posted for load restriction.

It carries about 100 vehicles a day, roughly 3% of them trucks, projected to reach 100 by 2040. The structure is 41 ft (12.5 m) long and 20 ft wide. If it were closed, the detour would be 19.9 mi (32 km).

CarriesUpper N Fork RD
CrossesN Fk Big Hole River 063
Location6M NW Wisdom
RouteCounty Highway 1004
StateMontana
Coordinates45.69518, -113.56111
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating5 US tons
Inventory rating5 US tons

Structure

MaterialSteel
DeckSteel plate
Main spans1
Design loadUnknown
Structure length41 ft (12.5 m)
Longest span40 ft (12.2 m)
Deck width20 ft (6.1 m)
Roadway width17 ft (5.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic100 (2025)
Projected traffic100 by 2040
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed19.9 mi (32 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty 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$149,000
NavigationNo navigation control on waterway

Frequently asked questions

When was Upper N Fork RD over N Fk Big Hole River 063 built?

It was built in 1978, making it 47 years old in 2025.

What condition is Upper N Fork RD over N Fk Big Hole River 063 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 Upper N Fork RD over N Fk Big Hole River 063 carry?

About 100 vehicles per day (2025 count), of which roughly 3% are trucks.

How long is Upper N Fork RD over N Fk Big Hole River 063?

The structure is 41 ft (12.5 m) long with a longest span of 40 ft (12.2 m) and a deck 20 ft wide.

Who owns Upper N Fork RD over N Fk Big Hole River 063?

It is owned by the County Highway Agency.