State profile · Near national median SD

Montana bridge safety

Condition ratings, load ratings, and structural-deficiency data for every public highway bridge in Montana - drawn straight from the FHWA National Bridge Inventory.

5,122
Public bridges
28.3%
Good condition
6.7%
Poor condition
6.7%
Structurally deficient

Data updated May 2026

Total Bridges

5,122

Public highway bridges in Montana

Good Condition

28.3%

1,447 bridges rated 7-9

-21.7pp vs 50% benchmark

Poor Condition

6.7%

343 bridges rated 0-4

Structurally Deficient

6.7%

343 bridges flagged for repair priority

-0.3pp vs national avg 7.0%

Montana vs national bridge condition

Montana - Good condition share 28.3%
National avg

Share of bridges rated 7-9 on the FHWA 0-9 scale (deck, superstructure, substructure all good).

Montana - Structurally deficient share 22.3%
National avg

Lower is better. Bar maxes at 30% (worst-state ceiling). National average sits at 7.0%.

Condition Distribution

Montana32.5%59.8%GoodFairPoor (structurally deficient)
Bridge inventory deck-condition mix - Montana (FHWA NBI)

Counties (56)

Beaverhead 217 Big Horn 136 Blaine 101 Broadwater 31 Carbon 77 Carter 39 Cascade 185 Chouteau 42 Custer 71 Daniels 32 Dawson 109 Deer Lodge 68 Fallon 35 Fergus 155 Flathead 195 Gallatin 207 Garfield 26 Glacier 68 Golden Valley 17 Granite 73 Hill 44 Jefferson 128 Judith Basin 48 Lake 111 Lewis and Clark 196 Liberty 11 Lincoln 190 Madison 84 McCone 44 Meagher 52 Mineral 152 Missoula 205 Musselshell 25 Park 124 Petroleum 26 Phillips 100 Pondera 96 Powder River 23 Powell 112 Prairie 46 Ravalli 149 Richland 96 Roosevelt 57 Rosebud 114 Sanders 116 Sheridan 66 Silver Bow 66 Stillwater 90 Sweet Grass 89 Teton 81 Toole 35 Treasure 26 Valley 103 Wheatland 26 Wibaux 24 Yellowstone 283

Montana vs nearby ranks

Adjacent states on the structurally deficient leaderboard (lower share = better)

States are ranked by share of bridges flagged structurally deficient, the FHWA classification for any span where deck, superstructure, or substructure carries a condition rating of 4 or below. Lower percentages indicate stronger maintenance funding and inspection follow-through. States here sit immediately above and below Montana on the same metric.

NC

North Carolina

6.16% top marginal rate
Structure
Progressive
Burden @ $100K
$18,901

HI

Hawaii

6.47% top marginal rate
Structure
Progressive
Burden @ $100K
$1,206
Selected

MT

Montana

6.70% top marginal rate
Structure
Progressive
Burden @ $100K
$5,122

NY

New York

6.90% top marginal rate
Structure
Progressive
Burden @ $100K
$19,132

KY

Kentucky

7.06% top marginal rate
Structure
Progressive
Burden @ $100K
$14,554

Bridges Needing Most Attention in Montana

Six lowest-condition bridges in Montana, ranked by composite NBI rating. Each is inspected at least every 24 months.

HWY 91 N

Poor

Over: BIG HOLE RIVER 041

22M N DILLON, Beaverhead, MT

Built 1940 Load: 2.7 t ADT: 155

SLEEPY HOLLOW LN

Structurally Deficient

Over: PRICKLY PEAR CREEK

3 M S MONTANA CITY, Jefferson, MT

Built 2010 Load: 2.7 t ADT: 100

CARBINE RD

Poor

Over: PABLO CANAL 026

4M W PABLO, Lake, MT

Built 1986 Load: 2.7 t ADT: 100

BOY SCOUT RD

Poor

Over: CLEARWATER RIVER 082

2M NW SEELEY LAKE, Missoula, MT

Built 1938 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

SHEEP CR RD

Structurally Deficient

Over: SHEEP CREEK 097

12M S CASCADE, Cascade, MT

Built 1950 Load: 3.6 t ADT: 68

All Bridges in Montana

I 15

Unknown

Over: INT MONIDA S 509

MONIDA, Beaverhead, MT

Built 1959 ADT: 100

I 15

Unknown

Over: INT MONIDA S 509

MONIDA, Beaverhead, MT

Built 1981 ADT: 100

I 15

Unknown

Over: SEP SNOWLINE STOCK LN

2.5M N MONIDA, Beaverhead, MT

Built 1981 ADT: 1

I 15

Unknown

Over: SEP SNOWLINE STOCK LN

2.5M N MONIDA, Beaverhead, MT

Built 1981 ADT: 1

I 15

Unknown

Over: INT SNOWLINE STOCK LN

5.6M S LIMA, Beaverhead, MT

Built 1981 ADT: 25

I 15

Unknown

Over: INT SNOWLINE STOCK LN

5.6M S LIMA, Beaverhead, MT

Built 1981 ADT: 25

I 15

Unknown

Over: INT LIMA-BAILEY ST

LIMA, Beaverhead, MT

Built 1959 ADT: 1,987

I 15

Unknown

Over: INT LIMA-BAILEY ST

LIMA, Beaverhead, MT

Built 1980 ADT: 1,987

I 15

Unknown

Over: SEP GOSMAN LANE

3.7M S DELL, Beaverhead, MT

Built 1967 ADT: 100

I 15

Unknown

Over: SEP GOSMAN LANE

3.7M S DELL, Beaverhead, MT

Built 1971 ADT: 100

I 15

Unknown

Over: INT DELL

DELL-MAIN ST, Beaverhead, MT

Built 1971 ADT: 100

I 15

Unknown

Over: INT DELL

DELL-MAIN ST, Beaverhead, MT

Built 1971 ADT: 100

I 15

Unknown

Over: INT KIDD

5.6M N DELL-KIDD LN, Beaverhead, MT

Built 1971 ADT: 100

I 15

Unknown

Over: INT KIDD

5.6M N DELL-KIDD LN, Beaverhead, MT

Built 1971 ADT: 100

I 15

Unknown

Over: INT RED ROCK-RED ROCK RD

7.4M S CLARK CANYON DAM, Beaverhead, MT

Built 1971 ADT: 100

I 15

Unknown

Over: INT RED ROCK-RED ROCK RD

7.4M S CLARK CANYON DAM, Beaverhead, MT

Built 1971 ADT: 100

I 15

Unknown

Over: SEP ROE LN

6.2M S CLARK CANYON DAM, Beaverhead, MT

Built 1962 ADT: 4

I 15

Unknown

Over: SEP ROE LN

6.2M S CLARK CANYON DAM, Beaverhead, MT

Built 1980 ADT: 4

I 15

Unknown

Over: BEAVERHD R-HIGH BRDG RD

1.2M N CLARK CANYON DAM, Beaverhead, MT

Built 1964 ADT: 100

I 15

Unknown

Over: BEAVERHD R-HIGH BRDG RD

1.2M N CLARK CANYON DAM, Beaverhead, MT

Built 1981 ADT: 100

I 15

Unknown

Over: SEP HIGH BRIDGE RD

3.7M N CLARK CANYON DAM, Beaverhead, MT

Built 1986 ADT: 100

I 15

Unknown

Over: SEP HIGH BRIDGE RD

3.7M N CLARK CANYON DAM, Beaverhead, MT

Built 1986 ADT: 100

I 15

Unknown

Over: SEP HIGH BRIDGE RD

6.2M N CLARK CANYON DAM, Beaverhead, MT

Built 1988 ADT: 100

I 15

Unknown

Over: SEP HIGH BRDGE RD

6.2M N CLARK CANYON DAM, Beaverhead, MT

Built 1988 ADT: 100

I 15

Unknown

Over: INT GRASSHOPPER CREEK

8M N CLARK CANYON DAM, Beaverhead, MT

Built 1988 ADT: 100

I 15

Unknown

Over: INT GRASSHOPPER CREEK

8M N CLARK CANYON DAM, Beaverhead, MT

Built 1988 ADT: 100

I 15

Unknown

Over: INT BARRETTS-REBICH LN

7.4M S DILLON, Beaverhead, MT

Built 1965 ADT: 100

I 15

Unknown

Over: INT BARRETTS-REBICH LN

7.4M S DILLON, Beaverhead, MT

Built 1980 ADT: 100

I 15

Unknown

Over: INT JACKSON-HWY 278

3.7M S DILLON, Beaverhead, MT

Built 1982 ADT: 1,144

I 15

Unknown

Over: INT JACKSON-HWY 278

3.7M S DILLON, Beaverhead, MT

Built 1982 ADT: 1,144

I 15

Unknown

Over: SEP PARK STREET

DILLON, Beaverhead, MT

Built 1983 ADT: 100

I 15

Unknown

Over: SEP PARK STREET

DILLON, Beaverhead, MT

Built 1983 ADT: 100

I 15

Unknown

Over: INT APEX-BIRCH CR RD

11.2M N DILLON, Beaverhead, MT

Built 1973 ADT: 30

I 15

Unknown

Over: INT APEX-BIRCH CR RD

11.2M N DILLON, Beaverhead, MT

Built 1973 ADT: 30

I 15

Unknown

Over: SEP COUNTY RD 203

11.2M S MELROSE, Beaverhead, MT

Built 1973 ADT: 100

I 15

Unknown

Over: SEP COUNTY RD 203

11.2M S MELROSE, Beaverhead, MT

Built 1973 ADT: 100

I 15

Unknown

Over: INT ROCK CR-BROWNES BR R

8M S MELROSE, Beaverhead, MT

Built 1973 ADT: 146

I 15

Unknown

Over: INT ROCK CR-BROWNES BR R

8M S MELROSE, Beaverhead, MT

Built 1973 ADT: 146

FRYING PAN RD

Unknown

Over: SEP I 15 126

3M N DILLON, Beaverhead, MT

Built 1973 ADT: 1,996

LOVERS LEAP RD

Unknown

Over: SEP I 15 12

1M N DILLON, Beaverhead, MT

Built 1973 ADT: 1,996

BOND RD

Unknown

Over: SEP I 15 12

7M N DILLON, Beaverhead, MT

Built 1973 ADT: 3,991

S 89

Unknown

Over: INT SOUTH DILLON I 15

DILLON, Beaverhead, MT

Built 1983 ADT: 2,826

S 89

Unknown

Over: LOCAL-BLACKTAIL CR-RR

DILLON, Beaverhead, MT

Built 1974 ADT: 2,660

S 89

Unknown

Over: INT NORTH DILLON I 15

DILLON, Beaverhead, MT

Built 1973 ADT: 2,602

S 324

Unknown

Over: INT HORSE PRAIRIE I 15

1M E CLARK CANYON DAM, Beaverhead, MT

Built 1962 ADT: 2,089

I 90

Unknown

Over: INT TOLUCA COUNTY ROAD

11.2M W HARDIN, Big Horn, MT

Built 1972 ADT: 100

I 90

Unknown

Over: INT TOLUCA COUNTY ROAD

11.2M W HARDIN, Big Horn, MT

Built 1972 ADT: 100

IRR - I 90

Unknown

Over: SARPY ROAD-S 384

1.2M E HARDIN, Big Horn, MT

Built 1971 ADT: 511

IRR - I 90

Unknown

Over: SARPY ROAD-S 384

1.2M E HARDIN, Big Horn, MT

Built 1971 ADT: 511

IRR - I 90

Unknown

Over: INT DUNMORE

5.6M N CROW AGENCY, Big Horn, MT

Built 1959 ADT: 100

Showing 1-50 of 5,122 bridges

Related

All states → | National rankings → | Understanding conditions → | SD bridges explained →
Data sourced from the FHWA National Bridge Inventory (NBI), latest released cycle. See our methodology for details. Retrieved and formatted by PlainBridges Editorial.

Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from the FHWA National Bridge Inventory (NBI). A "structurally deficient" rating is a repair-priority signal, not a closure or unsafe-to-cross designation. Consult a qualified civil engineer before making decisions based on this data.

Understanding Bridge Conditions

How FHWA rates bridge condition on a 0-9 scale.

Check Your Daily Bridges

How to look up bridge condition data for bridges on your route.

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

Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.