Structure L44105006+02001 · Rosebud County, MT

County Road 105 over W Blacktail Creek 007

Carries County Road 105 over W Blacktail Creek 007, 6m NE Ingomar.

Overall conditionPoor

Set by its lowest-rated component: Substructure at 4 of 9.

How ratings work
Deck6/9 · Satisfactory
Superstructure5/9 · Fair
Substructuresets the rating4/9 · Poor
Channelnot part of overall6/9 · Satisfactory
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT32 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 5/9Substructure 4/9 · sets the rating

32 ft end to end. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built194086 years old
Length32.5 ft9.9 m
Daily traffic100counted 2025
Last inspectedSeptember 2024every 24 months

Location

StateMontana
CountyRosebud
Location6m NE Ingomar
CarriesCounty Road 105
CrossesW Blacktail Creek 007
Coordinates46.62736, -107.26778

Physical Characteristics

MaterialSteel
DesignStringer/Multi-beam
Total Length32.5 ft (9.9 m)
Max Span30.2 ft (9.2 m)
Deck Width18.0 ft (5.5 m)
Deck Area54.5 sq m
Main Spans1
Year Built1940

Traffic

Avg Daily Traffic100 (2025)
Truck Traffic3%
Lanes On Bridge2

Inspection & Ownership

Last InspectionSeptember 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure NumberL44105006+02001

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.