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)

Sort:

YENNE POINT RD

Over: DRAIN TO WOODS BAY 103

WOODS BAY, Lake, MT

Built 2008 Load: 14.2 t ADT: 100

GLOVER RD

Over: PABLO 3A CANAL 037

4M S POLSON, Lake, MT

Built 1985 Load: 19.1 t ADT: 462

KOPP RD

Over: LITTLE BITTERROOT RV 062

8M NE HOT SPRINGS, Lake, MT

Built 1955 Load: 19.1 t ADT: 100

FISH HATCHERY RD

Over: POST CREEK 075

4M N ST IGNATIUS, Lake, MT

Built 1920 Load: 20.0 t ADT: 100

IRR - US 93

Over: FLATHEAD RIVER

POLSON, Lake, MT

Built 1966 Load: 20.0 t ADT: 8,324

TERRACE LAKE RD

Over: PABLO FEEDER CANAL 022

2M E RONAN, Lake, MT

Built 2009 Load: 21.8 t ADT: 100

TERRACE LAKE RD

Over: N CROW CREEK 021

1M E RONAN, Lake, MT

Built 1965 Load: 23.6 t ADT: 100

JOCKO CANYON RD

Over: JOCKO RIVER 012

7M E ARLEE, Lake, MT

Built 1976 Load: 24.5 t ADT: 100

N VALLEY CREEK RD

Over: VALLEY CREEK 055

3M S RAVALLI, Lake, MT

Built 1960 Load: 24.5 t ADT: 451

IRR - US 93

Over: POST CREEK

6M N ST IGNATIUS, Lake, MT

Built 1933 Load: 27.2 t ADT: 7,072

IRR - US 93

Over: DAYTON CREEK

DAYTON, Lake, MT

Built 1987 Load: 27.2 t ADT: 4,951

OLD US HWY 93

Over: MUD CREEK 097

4M N RONAN, Lake, MT

Built 2007 Load: 28.1 t ADT: 100

S 83 FH 15

Over: LOST CREEK

3M S SWAN LAKE, Lake, MT

Built 1953 Load: 28.1 t ADT: 1,166

BEAVERHEAD DR

Over: CROW CREEK 071

3M S RONAN, Lake, MT

Built 2003 Load: 29.0 t ADT: 100

IRR - S 212

Over: MISSION CREEK

MOIESE, Lake, MT

Built 1959 Load: 29.0 t ADT: 905

IRR - S 200

Over: JOCKO RIVER-RR

RAVALLI, Lake, MT

Built 1998 Load: 30.8 t ADT: 1,902

N VALLEY CREEK RD

Over: JOCKO RIVER 054

2M S RAVALLI, Lake, MT

Built 1970 Load: 32.7 t ADT: 451

N CROW RD

Over: PABLO FEEDER CANAL 007

3M SE PABLO, Lake, MT

Built 1978 Load: 32.7 t ADT: 100

S FERNDALE DR

Over: SWAN RIVER 102

2M SE FERNDALE, Lake, MT

Built 2007 Load: 34.5 t ADT: 100

THERESA ADAMS LN

Over: JOCKO RIVER 057

2M E ARLEE, Lake, MT

Built 1978 Load: 35.4 t ADT: 100

US 93

Over: MISSION CREEK

ST IGNATIUS, Lake, MT

Built 2006 Load: 38.1 t ADT: 6,822

US 93

Over: GRADE SEPARATION

2M N RAVALLI, Lake, MT

Built 2006 Load: 39.0 t ADT: 6,822

S 83 FH 15

Over: GOAT CREEK

12M S SWAN LAKE, Lake, MT

Built 2004 Load: 39.0 t ADT: 1,166

US 93

Over: JOCKO RIVER SIDE CHANNEL

7.5M N ARLEE, Lake, MT

Built 2006 Load: 39.9 t ADT: 8,330

FOREST ROAD

Over: SWAN RIVER

PORCUPINE CREEK ROAD, Lake, MT

Built 1956 Load: 40.8 t ADT: 20

OLD US HWY 93

Over: DAYTON CREEK 105

DAYTON, Lake, MT

Built 1930 Load: 41.7 t ADT: 100

US 93

Over: MUD CREEK

4M N RONAN, Lake, MT

Built 2008 Load: 59.9 t ADT: 5,692

US 93

Over: MUD CREEK

4M N RONAN, Lake, MT

Built 2007 Load: 63.5 t ADT: 5,692

JOCKO CANYON ROAD

Over: JOCKO RIVER 015

11M NE ARLEE, Lake, MT

Built 2003 Load: 77.8 t ADT: 100

EAGLE PASS TRAIL

Over: S KICKING HORSE RES 010

6M SE RONAN, Lake, MT

Built 1991 Load: 99.9 t ADT: 100

US 93

Over: WILDLIFE CROSSING

2 MILES NORTH OF RONAN, Lake, MT

Built 2007 ADT: 10,600

Foothill Road

Over: Mission Res Inlet 043

6 M SE St ignatius, Lake, MT

Built 2023 ADT: 100

MOLLMAN PASS TRAIL

Over: N KICKING HORSE RES 009

4M S RONAN, Lake, MT

Built 2023 ADT: 100

HILLSIDE ROAD

Over: POST CREEK

7 M SOUTH RONAN, Lake, MT

Built 2023 ADT: 100

GARCON GULCH ROAD

Over: LITTLE BITTERROOT RIVER

7 M N HOT SPRINGS, Lake, MT

Built 2022 Load: 13.6 t ADT: 100

SKYLINE DR

Over: PABLO 3A CANAL 039

3M S POLSON, Lake, MT

Built 2015 Load: 14.5 t ADT: 100

OLD FREIGHT ROAD

Over: MISSION CREEK 105

2M NW ST IGNATIUS, Lake, MT

Built 2012 Load: 14.9 t ADT: 100

MCDONALD LAKE RD

Over: POST CREEK 078

6M N ST IGNATIUS, Lake, MT

Built 2015 Load: 15.4 t ADT: 100

NO DATA ENTERED

Over: ARCHIBALD CR

NO DATA ENTERED, Lake, MT

Built 2004 Load: 19.8 t ADT: 50

SKYLINE DR

Over: PABLO FEEDER CANAL 040

2M SE POLSON, Lake, MT

Built 2011 Load: 19.9 t ADT: 100

JOCKO CANYON RD

Over: JOCKO RIVER 013

9M E ARLEE, Lake, MT

Built 1930 Load: 21.4 t ADT: 100

NFSR

Over: PONY CREEK

CONDON AREA, Lake, MT

Built 2008 Load: 21.7 t ADT: 40

BUFFALO BRIDGE RD

Over: FLATHEAD RIVER 084

10M W POLSON, Lake, MT

Built 1993 Load: 21.8 t ADT: 100

SKYLINE DR

Over: PABLO 3A CANAL 038

4M S POLSON, Lake, MT

Built 2013 Load: 21.8 t ADT: 100

NFSR

Over: CAT CREEK

CONDON AREA, Lake, MT

Built 2008 Load: 22.7 t ADT: 40

IRR BIA RTE 1114

Over: JOCKO RIVER

14.5 KM EAST OF ARLEE, Lake, MT

Built 1996 Load: 24.5 t ADT: 75

EAST POST CREEK RD

Over: POST CREEK 080

5 MI N OF ST IGNATIUS, Lake, MT

Built 2022 Load: 24.5 t ADT: 100

CANYON MILL RD

Over: PABLO FEEDER CANAL 008

2M NW RONAN, Lake, MT

Built 2014 Load: 24.5 t ADT: 100

SALMON PRAIRIE RD

Over: SWAN RIVER 091

22M S SWAN LAKE, Lake, MT

Built 1986 Load: 24.5 t ADT: 100

HILLSIDE ROAD

Over: MISSION CREEK

1.5 MILES E. ST. IGNATIUS, Lake, MT

Built 2021 Load: 25.4 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