Lake County, MT

111 public highway bridges

Lake County Bridge Snapshot

Lake County, Montana contains 111 public highway bridges in the FHWA National Bridge Inventory. Roughly 56.8% are rated “Good,” 27% “Fair,” 16.2% “Poor,” and 16.2% 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.

111
Total Bridges
56.8%
Good
16.2%
Poor
16.2%
Structurally Deficient

Condition Distribution

Good
56.8% (63)
Fair
27% (30)
Poor
16.2% (18)
SD
16.2% (18)

All Bridges (111)

FOREST ROAD

Good

Over: CREEK

NORTH FORK LOST CREEK, Lake, MT

Built 2005 Load: 25.9 t ADT: 30

MISSION DAM ROAD

Good

Over: MISSION CREEK

2M E ST IGNATIUS, Lake, MT

Built 2021 Load: 26.3 t ADT: 100

FOREST ROAD

Good

Over: CEDAR CREEK

FATTY-PIPER CONNECTOR, Lake, MT

Built 1985 Load: 26.6 t ADT: 10

KERR DAM RD

Good

Over: IRRIGATION CANAL

2M SW POLSON, Lake, MT

Built 1995 Load: 27.2 t ADT: 2,099

FOREST ROAD

Good

Over: DOG CREEK

NO DATA ENTERED, Lake, MT

Built 2013 Load: 28.2 t ADT: 40

FOREST ROAD

Good

Over: NORTH FORK LOST CREEK

NORTH LOST, Lake, MT

Built 2015 Load: 28.2 t ADT: 40

SYSTEM ROAD

Good

Over: FATTY CREEK

FATTY PIPER CONNECTOR, Lake, MT

Built 2013 Load: 28.8 t ADT: 40

FOREST ROAD

Good

Over: JIM CREEK

PECK LAKE ROAD, Lake, MT

Built 2016 Load: 29.2 t ADT: 50

FOREST ROAD

Good

Over: PIPER CREEK

PIPER CREEK ROAD, Lake, MT

Built 2015 Load: 29.5 t ADT: 40

STASSO ROAD

Good

Over: PABLO CANAL 37A4

5 MILES SOUTH OF POLSON, Lake, MT

Built 2020 Load: 29.9 t ADT: 100

FOREST ROAD

Good

Over: NORTH FORK LOST CREEK

SOUTH LOST, Lake, MT

Built 2014 Load: 30.1 t ADT: 40

STREAM

Good

Over: SOUTH MISSION RESERVIOR

6 MILES EAST ST IGNATIUS, Lake, MT

Built 2019 Load: 30.8 t ADT: 100

IRR BIA RTE 12

Good

Over: MISSION DAM CREEK

3.2KM E OF ST IGNATIUS,MT, Lake, MT

Built 2010 Load: 32.7 t ADT: 30

KAISER RD

Good

Over: PABLO CANAL 031

6M W RONAN, Lake, MT

Built 2014 Load: 32.7 t ADT: 100

MINESINGER TRAIL

Good

Over: PABLO FEEDER CANAL 003

6M SE POLSON, Lake, MT

Built 1978 Load: 32.7 t ADT: 100

COURVILLE TRAIL

Good

Over: PABLO FEEDER CANAL 006

7M SW POLSON, Lake, MT

Built 1978 Load: 32.7 t ADT: 100

US 93

Good

Over: WILDLIFE CROSSING

2M NE RONAN, Lake, MT

Built 2007 Load: 32.7 t ADT: 10,600

US 93

Good

Over: AGRICULTURAL CROSSING

2M N RONAN, Lake, MT

Built 2007 Load: 32.7 t ADT: 10,600

IRR - US 93

Good

Over: PABLO FEEDER CANAL

2M SE POLSON, Lake, MT

Built 2006 Load: 32.7 t ADT: 15,561

N RESEVOIR RD

Good

Over: PABLO FEEDER CANAL 085

5M S POLSON, Lake, MT

Built 2009 Load: 34.5 t ADT: 857

US 93

Good

Over: SABINE CREEK-WILDLIFE

1M S ST IGNATIUS, Lake, MT

Built 2006 Load: 35.4 t ADT: 6,822

LIL BITTERROOT RD

Good

Over: LITTLE BITTERROOT R 063

7M E HOT SPRINGS, Lake, MT

Built 2013 Load: 36.3 t ADT: 100

IRR - US 93

Good

Over: JOCKO RIVER

ARLEE, Lake, MT

Built 2005 Load: 36.3 t ADT: 8,330

S VALLEY CREEK RD

Good

Over: JOCKO RIVER 056

4M NW ARLEE, Lake, MT

Built 2012 Load: 37.2 t ADT: 122

FOREST SYSTEM ROAD

Good

Over: SWAN RIVER

NO DATA ENTERED, Lake, MT

Built 2012 Load: 37.3 t ADT: 50

US 93

Good

Over: WILDLIFE UNDERPASS

1M SE POLSON, Lake, MT

Built 2006 Load: 38.1 t ADT: 7,781

US 93

Good

Over: WILDLIFE UNDERPASS

S OF RAVALLI, Lake, MT

Built 2006 Load: 39.9 t ADT: 8,330

US 93

Good

Over: WILDLIFE UPASS-DRAINAGE

3M N ST IGNATIUS, Lake, MT

Built 2006 Load: 40.8 t ADT: 7,419

MICHAEL RD

Good

Over: PABLO FEEDER CANAL 024

3M NE RONAN, Lake, MT

Built 2014 Load: 41.7 t ADT: 100

US 93

Good

Over: WILDLIFE UNDERPASS

S OF RAVALLI, Lake, MT

Built 2006 Load: 41.7 t ADT: 8,330

HOWLETT ROAD

Good

Over: CROW CREEK

3 M SW RONAN, Lake, MT

Built 2021 Load: 42.6 t ADT: 100

US 93

Good

Over: WILDLIFE UNDERPASS

1M SE POLSON, Lake, MT

Built 2006 Load: 42.6 t ADT: 7,781

US 93

Good

Over: SPRING CREEK

3M S RAVALLI, Lake, MT

Built 2006 Load: 45.4 t ADT: 8,330

MCDONALD LAKE RD

Good

Over: PABLO FEEDER CANAL 077

7M NE ST IGNATIUS, Lake, MT

Built 2004 Load: 46.3 t ADT: 100

US 93

Good

Over: WILDLIFE UPASS-DRAINAGE

1M S RAVALLI, Lake, MT

Built 2006 Load: 46.3 t ADT: 8,330

US 93

Good

Over: WILDLIFE UPASS-RELIEF

1M N RAVALLI, Lake, MT

Built 2006 Load: 52.6 t ADT: 6,822

IRR BIA RTE 1012

Good

Over: NORTH FORK JOCKO RIVER

24.1KM NORTHEAST OF ARLEE, Lake, MT

Built 2003 Load: 66.6 t ADT: 30

US 93

Good

Over: WILDLIFE UPASS-DRAINAGE

1M N ST IGNATIUS, Lake, MT

Built 2006 Load: 76.2 t ADT: 7,419

US 93

Good

Over: WILDLIFE UPASS-DRAINAGE

2M N ST IGNATIUS, Lake, MT

Built 2006 Load: 78.9 t ADT: 7,419

US 93

Good

Over: WILDLIFE UPASS-DRAINAGE

1M N RAVALLI, Lake, MT

Built 2006 Load: 85.3 t ADT: 6,822

FOOTHILL RD

Good

Over: MISSION CREEK 044

2M E ST IGNATIUS, Lake, MT

Built 1988 Load: 87.1 t ADT: 100

US 93

Good

Over: WILDLIFE UPASS-DRAINAGE

2M S ST IGNATIUS, Lake, MT

Built 2006 Load: 99.9 t ADT: 6,822

US 93

Good

Over: WILDLIFE UPASS-DRAINAGE

2M S ST IGNATIUS, Lake, MT

Built 2006 Load: 99.9 t ADT: 6,822

CARBINE RD

Poor

Over: PABLO CANAL 026

4M W PABLO, Lake, MT

Built 1986 Load: 2.7 t ADT: 100

ASHLEY LAKE RD

Poor

Over: PABLO FEEDER CANAL 045

5M NE ST IGNATIUS, Lake, MT

Built 1965 Load: 3.0 t ADT: 100

LIL BITTERROOT RD

Poor

Over: LITTLE BITTERROOT R 061

7M NE HOT SPRINGS, Lake, MT

Built 1965 Load: 12.7 t ADT: 100

SEIFERT RD

Poor

Over: PABLO A CANAL 083

6M SW POLSON, Lake, MT

Built 1960 Load: 15.4 t ADT: 100

ROCKY BUTTE RD

Poor

Over: CROW CREEK 070

2M SW RONAN, Lake, MT

Built 1986 Load: 17.2 t ADT: 126

S MAIN AVE

Poor

Over: MISSION CREEK 052

ST IGNATIUS-S MAIN ST, Lake, MT

Built 1929 Load: 20.5 t ADT: 2,220

EAGLE PASS TRAIL

Poor

Over: PABLO FEEDER CANAL 104

9M NE ST IGNATIUS, Lake, MT

Built 1977 Load: 21.8 t ADT: 100

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

Related

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