US Bridges

County Road 143 over Unnamed Creek 059

FairPosted for load

Big Horn County, Montana · 34M E Decker · Structure no. L02143010+09001

Built
1950
75 years old
Condition
Fair
inspected July 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
24 ft
1 main span
Daily traffic
100
2025 count
Owner
County
County Highway Agency

About this bridge

County Road 143 over Unnamed Creek 059 is a steel stringer/multi-beam or girder carrying County Road 143 over Unnamed Creek 059 in Big Horn County, Montana. It was built in 1950, so it is 75 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. 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 24 ft (7.3 m) long and 14 ft wide. If it were closed, the detour would be 34.2 mi (55 km).

Location

Open in Google Maps
CarriesCounty Road 143
CrossesUnnamed Creek 059
Location34M E Decker
RouteCounty Highway 2143
CountyBig Horn County
StateMontana
Coordinates45.00208, -106.42539
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
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 inspectionJuly 2024
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating9 US tons
Inventory rating7.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckWood or timber
Main spans1
Design loadUnknown
Structure length24 ft (7.3 m)
Longest span23 ft (7 m)
Deck width14 ft (4.4 m)
Roadway width13 ft (4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic100 (2025)
Projected traffic100 by 2040
Trucks3%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed34.2 mi (55 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was County Road 143 over Unnamed Creek 059 built?

It was built in 1950, making it 75 years old in 2025.

What condition is County Road 143 over Unnamed Creek 059 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 2024.

How much traffic does County Road 143 over Unnamed Creek 059 carry?

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

How long is County Road 143 over Unnamed Creek 059?

The structure is 24 ft (7.3 m) long with a longest span of 23 ft (7 m) and a deck 14 ft wide.

Who owns County Road 143 over Unnamed Creek 059?

It is owned by the County Highway Agency.