US Bridges

County Road 111 over Horse Prairie Creek 031

FairPosted for load

Beaverhead County, Montana · 8M W Grant · Structure no. L01111001+03001

Built
1920
105 years old
Condition
Fair
inspected October 2023
Type
Truss - Thru
Steel
Length
54 ft
1 main span
Daily traffic
100
2025 count
Owner
County
County Highway Agency

About this bridge

County Road 111 over Horse Prairie Creek 031 is a steel truss - thru carrying County Road 111 over Horse Prairie Creek 031 in Beaverhead County, Montana. It was built in 1920, so it is 105 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 54 ft (16.5 m) long and 18 ft wide. If it were closed, the detour would be 9.9 mi (16 km).

Location

Open in Google Maps
CarriesCounty Road 111
CrossesHorse Prairie Creek 031
Location8M W Grant
RouteCounty Highway 1111
CountyBeaverhead County
StateMontana
Coordinates45.01414, -113.2261
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation2: Basically intolerable, requiring high priority of replacement
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating17 US tons
Inventory rating10 US tons

Structure

Structure typeTruss - Thru
MaterialSteel
DeckWood or timber
Main spans1
Design loadUnknown
Structure length54 ft (16.5 m)
Longest span54 ft (16.5 m)
Deck width18 ft (5.5 m)
Roadway width18 ft (5.4 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 closed9.9 mi (16 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$87,000
NavigationNo navigation control on waterway

Frequently asked questions

When was County Road 111 over Horse Prairie Creek 031 built?

It was built in 1920, making it 105 years old in 2025.

What condition is County Road 111 over Horse Prairie Creek 031 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 October 2023.

How much traffic does County Road 111 over Horse Prairie Creek 031 carry?

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

How long is County Road 111 over Horse Prairie Creek 031?

The structure is 54 ft (16.5 m) long with a longest span of 54 ft (16.5 m) and a deck 18 ft wide.

Who owns County Road 111 over Horse Prairie Creek 031?

It is owned by the County Highway Agency.