Lewis and Clark County, MT

196 public highway bridges

Lewis and Clark County Bridge Snapshot

Lewis and Clark County, Montana contains 196 public highway bridges in the FHWA National Bridge Inventory. Roughly 51.5% are rated “Good,” 30.6% “Fair,” 4.6% “Poor,” and 4.6% 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.

196

Total Bridges

51.5%

Good

4.6%

Poor

4.6%

Structurally Deficient

Condition Distribution

Good

51.5% (101)

Fair

30.6% (60)

Poor

4.6% (9)

SD

4.6% (9)

All Bridges (196)

Sort:

I 15

Over: SEP SIERRA RD E

4M N HELENA, Lewis and Clark, MT

Built 1962 ADT: 3,264

I 15

Over: SEP SIERRA RD E

4M N HELENA, Lewis and Clark, MT

Built 1962 ADT: 3,264

I 15

Over: INT GATES OF THE MTNS

17M S WOLF CREEK, Lewis and Clark, MT

Built 1962 ADT: 431

I 15

Over: INT GATES OF THE MTNS

17M S WOLF CREEK, Lewis and Clark, MT

Built 1962 ADT: 431

I 15

Over: INT SEIBEN

10M S WOLF CREEK, Lewis and Clark, MT

Built 1962 ADT: 37

I 15

Over: INT SEIBEN

10M S WOLF CREEK, Lewis and Clark, MT

Built 1962 ADT: 37

I 15

Over: INT SPRING CREEK-RR

7M S WOLF CREEK, Lewis and Clark, MT

Built 1964 ADT: 30

I 15

Over: INT SPRING CREEK-RR

7M S WOLF CREEK, Lewis and Clark, MT

Built 1964 ADT: 30

I 15

Over: SEP LYONS CREEK ROAD

6M S WOLF CREEK, Lewis and Clark, MT

Built 1964 ADT: 100

I 15

Over: SEP LYONS CREEK ROAD

6M S WOLF CREEK, Lewis and Clark, MT

Built 1964 ADT: 100

I 15

Over: INT WOLF CREEK

WOLF CREEK, Lewis and Clark, MT

Built 1966 ADT: 421

I 15

Over: INT WOLF CREEK

WOLF CREEK, Lewis and Clark, MT

Built 1966 ADT: 421

I 15

Over: INT CRAIG

CRAIG, Lewis and Clark, MT

Built 1967 ADT: 773

I 15

Over: INT CRAIG

CRAIG, Lewis and Clark, MT

Built 1967 ADT: 773

I 15

Over: SEP MISSOURI RVR-CO RD

2M N CRAIG, Lewis and Clark, MT

Built 1967 ADT: 327

I 15

Over: SEP MISSOURI RVR-CO RD

2M N CRAIG, Lewis and Clark, MT

Built 1967 ADT: 327

I 15

Over: MISSOURI RVR-RR-LOCAL

5M N CRAIG, Lewis and Clark, MT

Built 1971 ADT: 327

I 15

Over: MISSOURI RVR-RR-LOCAL

5M N CRAIG, Lewis and Clark, MT

Built 1971 ADT: 327

SADDLE DRIVE

Over: S HELENA INT I 15 156

1M S HELENA, Lewis and Clark, MT

Built 2007 ADT: 7,626

S HOWIE ST

Over: REEDERS ALLEY 001

HELENA-REEDERS ALLEY, Lewis and Clark, MT

Built 1881 ADT: 100

PROSPECT AVE-US 12

Over: INT CAPITOL-I 15

HELENA-PROSPECT AVE, Lewis and Clark, MT

Built 1961 ADT: 7,626

PROSPECT AVE-US 12

Over: INT CAPITOL-I 15

HELENA-PROSPECT AVE, Lewis and Clark, MT

Built 1961 ADT: 11,699

US 287

Over: INT AUGUSTA I 15

1M NE WOLF CREEK, Lewis and Clark, MT

Built 1966 ADT: 2,522

LINCOLN RD

Over: INT LINCOLN-I 15

10M N HELENA, Lewis and Clark, MT

Built 1962 ADT: 2,340

E CUSTER AVE

Over: INT CUSTER AVE-I 15

HELENA-E CUSTER AVE, Lewis and Clark, MT

Built 2012 ADT: 6,190

CEDAR ST

Over: INT CEDAR ST-I 15

HELENA-CEDAR ST, Lewis and Clark, MT

Built 2002 ADT: 9,322

BIRDTAIL RD

Over: FLAT CREEK 036

8M SE BOWMANS, Lewis and Clark, MT

Built 1901 Load: 2.7 t ADT: 100

AUGUSTA RD

Over: DEARBORN RIVER 011

18M S AUGUSTA, Lewis and Clark, MT

Built 1896 Load: 4.2 t ADT: 31

CHEVALLIER DR

Over: LITTLE PRICKLY PEAR 109

7M SW SIEBEN INT, Lewis and Clark, MT

Built 1905 Load: 4.5 t ADT: 37

MCDONALD LN

Over: LTL PRICKLY PEAR CRK 151

3M W CANYON CREEK, Lewis and Clark, MT

Built 1990 Load: 4.5 t ADT: 100

AUGUSTA-CLEMONS RD

Over: ELK CREEK 029

2M SW AUGUSTA, Lewis and Clark, MT

Built 1915 Load: 7.3 t ADT: 100

HEAD LN

Over: SEVEN MILE CREEK 149

5M NW HELENA, Lewis and Clark, MT

Built 1982 Load: 11.0 t ADT: 352

HART LN

Over: HELENA VALLEY CANAL 088

4M NE EAST HELENA, Lewis and Clark, MT

Built 1957 Load: 14.5 t ADT: 126

S 200

Over: DEARBORN RIVER

25M SW SIMMS, Lewis and Clark, MT

Built 1949 Load: 17.2 t ADT: 1,382

MINNEHAHA ROAD

Over: TEN MILE CREEK

INTERSECT MINNEHAHA&TENMI, Lewis and Clark, MT

Built 1955 Load: 18.1 t ADT: 30

BEAVER CREEK ROAD

Over: BEAVER CREEK

BEAVER CREEK 3, Lewis and Clark, MT

Built 2004 Load: 18.5 t ADT: 50

HOGUM CK ROAD

Over: BLACKFOOT RIVER

HOGUM-BLACKFOOT, Lewis and Clark, MT

Built 1965 Load: 18.8 t ADT: 46

HOGUM CK ROAD

Over: HOGUM CREEK

HOGUM, Lewis and Clark, MT

Built 1962 Load: 19.1 t ADT: 46

YORK RD

Over: MISSOURI RIVER

14M NE HELENA, Lewis and Clark, MT

Built 1982 Load: 19.1 t ADT: 470

SUCKER KP KL ROAD

Over: COPPER CREEK

KEEP KOOL-COPPER, Lewis and Clark, MT

Built 1962 Load: 19.4 t ADT: 34

US 287

Over: DEARBORN RIVER

14M NW WOLF CREEK, Lewis and Clark, MT

Built 1963 Load: 20.0 t ADT: 457

N MONTANA AVE

Over: HELENA VALLEY CANAL

1M N HELENA, Lewis and Clark, MT

Built 1958 Load: 20.0 t ADT: 11,526

NFSR 330

Over: LANDERS FORK

LANDERS FORK, Lewis and Clark, MT

Built 1977 Load: 21.7 t ADT: 21

APPLEGATE DR

Over: HELENA VALLEY CANAL 115

6M NW HELENA, Lewis and Clark, MT

Built 1958 Load: 21.8 t ADT: 1,526

S CRUSE AVE

Over: PEDESTRIAN UNDERPASS

HELENA-S CRUSE AVE, Lewis and Clark, MT

Built 1972 Load: 21.8 t ADT: 1,580

CRAIG FRONTAGE RD

Over: WEGNER CREEK 055

CRAIG, Lewis and Clark, MT

Built 1934 Load: 23.6 t ADT: 327

S 200

Over: LANDERS FORK

4M NE LINCOLN, Lewis and Clark, MT

Built 1938 Load: 23.6 t ADT: 1,982

LINCOLN RD W

Over: LITTLE PRICKLY PEAR CR

2M NW CANYON CREEK, Lewis and Clark, MT

Built 1949 Load: 23.6 t ADT: 394

LINCOLN RD W

Over: CANYON CREEK

6M NW CANYON CREEK, Lewis and Clark, MT

Built 1949 Load: 23.6 t ADT: 394

NELSON RD

Over: BEAVER CREEK 121

NELSON, Lewis and Clark, MT

Built 1975 Load: 24.4 t ADT: 233

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 5, 2026