US Bridges

S 278 over Grasshopper Creek

Fair

Beaverhead County, Montana · 21M W Dillon · Structure no. S00278018+06001

Built
1957
68 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Wood or Timber
Length
50 ft
2 main spans
Daily traffic
668
2023 count
Owner
State
State Highway Agency

About this bridge

S 278 over Grasshopper Creek is a wood or timber stringer/multi-beam or girder carrying S 278 over Grasshopper Creek in Beaverhead County, Montana. It was built in 1957, so it is 68 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.

It carries about 668 vehicles a day, roughly 3% of them trucks, projected to reach 701 by 2043. The structure is 50 ft (15.2 m) long and 26 ft wide. If it were closed, the detour would be 29.8 mi (48 km).

Location

Open in Google Maps
CarriesS 278
CrossesGrasshopper Creek
Location21M W Dillon
RouteState Highway 278
CountyBeaverhead County
StateMontana
Coordinates45.21535, -113.03956
Functional classRural Minor Arterial

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionAugust 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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating45 US tons
Inventory rating31 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialWood or Timber
DeckWood or timber
Main spans2
Design loadHS 15
Structure length50 ft (15.2 m)
Longest span25 ft (7.6 m)
Deck width26 ft (8 m)
Roadway width25 ft (7.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic668 (2023)
Projected traffic701 by 2043
Trucks3%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.8 mi (48 km)
TollOn a free road
National Highway SystemNo

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 S 278 over Grasshopper Creek built?

It was built in 1957, making it 68 years old in 2025.

What condition is S 278 over Grasshopper Creek 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 2024.

How much traffic does S 278 over Grasshopper Creek carry?

About 668 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is S 278 over Grasshopper Creek?

The structure is 50 ft (15.2 m) long with a longest span of 25 ft (7.6 m) and a deck 26 ft wide.

Who owns S 278 over Grasshopper Creek?

It is owned by the State Highway Agency.