Jefferson County, MT

128 public highway bridges

Jefferson County Bridge Snapshot

Jefferson County, Montana contains 128 public highway bridges in the FHWA National Bridge Inventory. Roughly 10.9% are rated “Good,” 46.9% “Fair,” 5.5% “Poor,” and 5.5% 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.

128

Total Bridges

10.9%

Good

5.5%

Poor

5.5%

Structurally Deficient

Condition Distribution

Good

10.9% (14)

Fair

46.9% (60)

Poor

5.5% (7)

SD

5.5% (7)

All Bridges (128)

Sort:

I 15

Over: INT WOODVILLE

3.1M N BUTTE, Jefferson, MT

Built 1976 ADT: 100

I 15

Over: INT WOODVILLE

3.1M N BUTTE, Jefferson, MT

Built 1976 ADT: 100

I 15

Over: SEP SAWMILL GULCH

6.2M N BUTTE, Jefferson, MT

Built 1976 ADT: 100

I 15

Over: SEP SAWMILL GULCH

6.2M N BUTTE, Jefferson, MT

Built 1976 ADT: 100

I 15

Over: INT TRASK-LOWLAND RD

8M N BUTTE, Jefferson, MT

Built 1976 ADT: 100

I 15

Over: INT TRASK-LOWLAND RD

8M N BUTTE, Jefferson, MT

Built 1976 ADT: 100

I 15

Over: SEP ELK PARK-E ELK PARK

12.4M N BUTTE, Jefferson, MT

Built 1985 ADT: 100

I 15

Over: SEP ELK PARK-E ELK PARK

12.4M N BUTTE, Jefferson, MT

Built 1985 ADT: 100

I 15

Over: INT BERNICE-BOULDER R RD

5M S BASIN, Jefferson, MT

Built 1985 ADT: 87

I 15

Over: INT BERNICE-BOULDER R RD

5M S BASIN, Jefferson, MT

Built 1985 ADT: 87

I 15

Over: SEP SILVER AVE-BASIN CR

BASIN, Jefferson, MT

Built 1985 ADT: 100

I 15

Over: INT BASIN

BASIN, Jefferson, MT

Built 1985 ADT: 100

I 15

Over: BOULDER RVR-FRONTAGE RD

1.9M E BASIN, Jefferson, MT

Built 1982 ADT: 100

I 15

Over: INT HIGH ORE

3.7M E BASIN, Jefferson, MT

Built 1982 ADT: 100

I 15

Over: SEP GALENA GULCH ROAD

4.3M E BASIN, Jefferson, MT

Built 1981 ADT: 100

I 15

Over: BOULDER RVR-ACCESS RD

2.5M W BOULDER, Jefferson, MT

Built 1980 ADT: 100

I 15

Over: BOULDER RVR-ACCESS RD

2.5M W BOULDER, Jefferson, MT

Built 1980 ADT: 100

I 15

Over: SEP DEPOT HILL ROAD

BOULDER, Jefferson, MT

Built 1973 ADT: 100

I 15

Over: SEP DEPOT HILL ROAD

BOULDER, Jefferson, MT

Built 1973 ADT: 100

I 15

Over: SEP AMAZON RD

3.7M N BOULDER, Jefferson, MT

Built 1973 ADT: 100

I 15

Over: SEP AMAZON ROAD

3.7M N BOULDER, Jefferson, MT

Built 1973 ADT: 100

I 15

Over: SEP TROY CREEK ROAD

3.7M S JEFFERSON CITY, Jefferson, MT

Built 1973 ADT: 100

I 15

Over: SEP TROY CREEK ROAD

3.7M S JEFFERSON CITY, Jefferson, MT

Built 1973 ADT: 100

I 15

Over: INT CLANCY

CLANCY, Jefferson, MT

Built 1969 ADT: 100

I 15

Over: INT CLANCY

CLANCY, Jefferson, MT

Built 1969 ADT: 100

I 15

Over: SEP LUMP GULCH ROAD

0.6M N CLANCY, Jefferson, MT

Built 1969 ADT: 100

I 15

Over: SEP LUMP GULCH ROAD

0.6M N CLANCY, Jefferson, MT

Built 1969 ADT: 100

I 15

Over: SEP S HWY 282

1.9M S MONTANA CITY, Jefferson, MT

Built 1968 ADT: 100

I 15

Over: SEP S HWY 282

1.9M S MONTANA CITY, Jefferson, MT

Built 1968 ADT: 100

I 90

Over: INT PIPESTONE

6.8M W WHITEHALL, Jefferson, MT

Built 1966 ADT: 100

I 90

Over: INT PIPESTONE

6.8M W WHITEHALL, Jefferson, MT

Built 1966 ADT: 100

I 90

Over: SEP SHEEP CAMP RD

3.7M W WHITEHALL, Jefferson, MT

Built 1966 ADT: 100

I 90

Over: SEP SHEEP CAMP RD

3.7M W WHITEHALL, Jefferson, MT

Built 1966 ADT: 100

I 90 EASTBOUND

Over: INT WHITEHALL

WHITEHALL, Jefferson, MT

Built 1966 ADT: 100

I 90 WESTBOUND

Over: INT WHITEHALL

WHITEHALL, Jefferson, MT

Built 1966 ADT: 100

I 90 EASTBOUND

Over: P 69

3.1M W CARDWELL, Jefferson, MT

Built 1968 ADT: 1,002

I 90 WESTBOUND

Over: P 69

3.1M W CARDWELL, Jefferson, MT

Built 1968 ADT: 1,002

I 90

Over: INT CARDWELL-S 359

CARDWELL, Jefferson, MT

Built 1968 ADT: 1,389

I 90

Over: INT CARDWELL-S 359

CARDWELL, Jefferson, MT

Built 1968 ADT: 1,389

I 90

Over: SEP COUNTY ROAD

7.4M E CARDWELL, Jefferson, MT

Built 1969 ADT: 100

HOMESTAKE PASS

Over: INT HOMESTAKE-I 90 005

HOMESTAKE PASS, Jefferson, MT

Built 1966 ADT: 11,082

PAUL GULCH RD

Over: SEP I 90 002

WHITEHALL, Jefferson, MT

Built 1966 ADT: 10,289

MILLIGAN CANYON RD

Over: INT MILLIGAN-I 90 004

11M W CARDWELL, Jefferson, MT

Built 1969 ADT: 5,527

FRONTAGE ROAD 925

Over: INT JEFF CITY-I 15 001

JEFFERSON CITY, Jefferson, MT

Built 1970 ADT: 2,501

S HILLS RD-HWY 282

Over: I-15

1M N MONTANA CITY, Jefferson, MT

Built 1968 ADT: 5,736

S 69

Over: INT BOULDER I 15

BOULDER, Jefferson, MT

Built 1973 ADT: 1,904

S 518

Over: INT MONTANA CITY-I 15

MONTANA CITY, Jefferson, MT

Built 1968 ADT: 5,736

NON MAINTAINED TRL

Over: BISON CREEK

11M N ELK PARK, Jefferson, MT

Built 1984 ADT: 100

NON MAINTAINED TRL

Over: BISON CREEK

12M N ELK PARK, Jefferson, MT

Built 1984 ADT: 100

BOULDER CUT OFF RD

Over: BOULDER RIVER 003

10M NE WHITEHALL, Jefferson, MT

Built 1981 Load: 3.6 t ADT: 100

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

Reviewed byPlainbridges Editorial, Plain Bridges Editorial Team · June 6, 2026