Petroleum County, MT

26 public highway bridges

Petroleum County Bridge Snapshot

Petroleum County, Montana contains 26 public highway bridges in the FHWA National Bridge Inventory. Roughly 30.8% are rated “Good,” 53.8% “Fair,” 15.4% “Poor,” and 15.4% are classified as structurally deficient — the federal designation for spans whose deck, superstructure, or substructure has been rated 4 or below on the 0–9 NBI scale. Structurally deficient does not mean unsafe to cross; it means the bridge is on the priority list for repair or replacement.

Inspections in MT are conducted by certified engineers from the state Department of Transportation on a 24-month cycle, and results are reported back to the FHWA each spring. The list below shows every NBI-tracked bridge in the county, sorted by inventory load rating. Use the “Sort by” controls to surface the lowest-rated spans first, and click any row for full inspection history, traffic counts, and condition trends.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

26
Total Bridges
30.8%
Good
15.4%
Poor
15.4%
Structurally Deficient

Condition Distribution

Good
30.8% (8)
Fair
53.8% (14)
Poor
15.4% (4)
SD
15.4% (4)

All Bridges (26)

PETROLIA BENCH RD

Fair

Over: MCDONALD CREEK 003

9M E WINNETT, Petroleum, MT

Built 1940 Load: 5.4 t ADT: 58

MAIN ST

Fair

Over: MCDONALD CREEK 015

WINNETT-MAIN ST, Petroleum, MT

Built 1940 Load: 5.4 t ADT: 98

TEIGEN LOOP

Fair

Over: MCDONALD CREEK 032

S TEIGEN, Petroleum, MT

Built 2012 Load: 9.1 t ADT: 100

CEMETARY RD

Fair

Over: SO FK BUFFALO CR 011

6M NW WINNETT, Petroleum, MT

Built 1960 Load: 11.8 t ADT: 100

S 244

Fair

Over: FLATWILLOW CREEK

6M SW FLATWILLOW, Petroleum, MT

Built 1939 Load: 21.8 t ADT: 207

DOVETAIL VALENTINE

Fair

Over: BUFFALO CREEK 006

6M N WINNETT, Petroleum, MT

Built 1983 Load: 22.7 t ADT: 100

S 244

Fair

Over: DRAINAGE

10M SW FLATWILLOW, Petroleum, MT

Built 1940 Load: 22.7 t ADT: 207

S 244

Fair

Over: MCDONALD CREEK

WINNETT, Petroleum, MT

Built 1941 Load: 22.7 t ADT: 244

S 244

Fair

Over: PIKE CREEK

FLATWILLOW, Petroleum, MT

Built 1939 Load: 23.6 t ADT: 232

S 244

Fair

Over: DRAINAGE

FLATWILLOW, Petroleum, MT

Built 1935 Load: 23.6 t ADT: 232

ROAD 317

Fair

Over: ALKALI CREEK

SECT 1 T18N R29E, Petroleum, MT

Built 1963 Load: 24.5 t ADT: 2

S 200

Fair

Over: BOX ELDER CREEK

8M E WINNETT, Petroleum, MT

Built 1953 Load: 29.9 t ADT: 630

PETROLIA LAKE RD

Fair

Over: MCDONALD CREEK 014

6M E WINNETT, Petroleum, MT

Built 1980 Load: 32.7 t ADT: 100

BLAKESLEE RD

Fair

Over: CANAL 030

7M N TEIGEN, Petroleum, MT

Built 1978 Load: 32.7 t ADT: 100

Flatwillow Road

Good

Over: Flatwilow Creek

12M S Winnett, Petroleum, MT

Built 2023 ADT: 100

DOVETAIL VALENTINE

Good

Over: BOX ELDER CREEK 007

6M N WINNETT, Petroleum, MT

Built 1982 Load: 20.9 t ADT: 100

WELTER DIVIDE RD

Good

Over: BOX ELDER CREEK 010

13M NE TEIGEN, Petroleum, MT

Built 1994 Load: 25.4 t ADT: 100

S 500

Good

Over: FLATWILLOW CREEK

6M SW MOSBY, Petroleum, MT

Built 1962 Load: 26.3 t ADT: 31

S 500

Good

Over: NORTH WILLOW CREEK

13M SW MOSBY, Petroleum, MT

Built 1975 Load: 27.2 t ADT: 33

WILDHORSE RD

Good

Over: BOX ELDER CREEK 012

13M NW WINNETT, Petroleum, MT

Built 1978 Load: 32.7 t ADT: 100

KELLY RD

Good

Over: FLATWILLOW CREEK 013

8M S WINNETT, Petroleum, MT

Built 2013 Load: 34.3 t ADT: 58

HORSE CAMP ROAD

Good

Over: SACAGAWEA RIVER

38 MILES NORTH OF WINNETT, Petroleum, MT

Built 2015 Load: 37.2 t ADT: 100

OLD CAT CREEK RD

Poor

Over: BOX ELDER CREEK 008

5M NE WINNETT, Petroleum, MT

Built 1930 Load: 5.4 t ADT: 100

HUGHES LN

Poor

Over: FLATWILLOW CREEK 016

16M S WINNETT, Petroleum, MT

Built 1950 Load: 10.0 t ADT: 100

ROAD 317

Poor

Over: DRAG CREEK

SECT 11 T18N R29E, Petroleum, MT

Built 1963 Load: 20.9 t ADT: 2

S 244

Poor

Over: YELLOW WATER CR-ELK CR

5M S WINNETT, Petroleum, MT

Built 1948 Load: 29.9 t ADT: 232

Read our methodology — how this data is sourced, computed, and verified.

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Data sourced from official U.S. government datasets. See our methodology for details. Retrieved and formatted by PlainBridges Editorial