US Bridges

1st ST NW over Big Ditch 005

Fair

Stillwater County, Montana · 0.5M NW Park City · Structure no. L48378000+07401

Built
1935
90 years old
Condition
Fair
inspected April 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
32 ft
1 main span
Daily traffic
100
2025 count
Owner
County
County Highway Agency

About this bridge

1st ST NW over Big Ditch 005 is a steel stringer/multi-beam or girder carrying 1st ST NW over Big Ditch 005 in Stillwater County, Montana. It was built in 1935, so it is 90 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 100 vehicles a day, roughly 3% of them trucks, projected to reach 100 by 2040. The structure is 32 ft (9.7 m) long and 16 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
Carries1st ST NW
CrossesBig Ditch 005
Location0.5M NW Park City
RouteCounty Highway 378
CountyStillwater County
StateMontana
Coordinates45.63643, -108.92005
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 protection7 GoodSome minor problems.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
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 rating46 US tons
Inventory rating28 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length32 ft (9.7 m)
Longest span32 ft (9.7 m)
Deck width16 ft (4.9 m)
Roadway width16 ft (4.9 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 closed123.7 mi (199 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 1st ST NW over Big Ditch 005 built?

It was built in 1935, making it 90 years old in 2025.

What condition is 1st ST NW over Big Ditch 005 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 April 2024.

How much traffic does 1st ST NW over Big Ditch 005 carry?

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

How long is 1st ST NW over Big Ditch 005?

The structure is 32 ft (9.7 m) long with a longest span of 32 ft (9.7 m) and a deck 16 ft wide.

Who owns 1st ST NW over Big Ditch 005?

It is owned by the County Highway Agency.