State profile · Below national median SD

Idaho bridge safety

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

1,742
Public bridges
33.3%
Good condition
5.5%
Poor condition
5.5%
Structurally deficient

Total Bridges

1,742

Public highway bridges in Idaho

Good Condition

33.3%

580 bridges rated 7-9

-16.7pp vs 50% benchmark

Poor Condition

5.5%

96 bridges rated 0-4

Structurally Deficient

5.5%

96 bridges flagged for repair priority

-1.5pp vs national avg 7.0%

Idaho vs national bridge condition

Idaho — Good condition share 33.3%
National avg

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

Idaho — Structurally deficient share 18.4%
National avg

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

Condition Distribution

Bridge inventory deck-condition mix — Idaho (FHWA NBI)

Idaho33.295063145809415%55.166475315729045%GoodFairPoorStructurally Deficient
Bridge inventory deck-condition mix — Idaho (FHWA NBI)

Counties (44)

Ada 81 Adams 42 Bannock 25 Bear Lake 13 Benewah 15 Bingham 75 Blaine 39 Boise 41 Bonner 47 Bonneville 50 Boundary 52 Butte 14 Camas 26 Canyon 77 Caribou 12 Cassia 38 Clark 18 Clearwater 65 Custer 81 Elmore 45 Franklin 4 Fremont 46 Gem 16 Gooding 25 Idaho 130 Jefferson 55 Jerome 26 Kootenai 60 Latah 26 Lemhi 73 Lewis 6 Lincoln 16 Madison 27 Minidoka 19 Nez Perce 19 Oneida 2 Owyhee 20 Payette 9 Power 13 Shoshone 139 Teton 13 Twin Falls 35 Valley 82 Washington 25

Idaho 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 Idaho on the same metric.

20

Kansas

5.25% top marginal rate
Structure
Progressive
Burden @ $100K
$23,867

56

Wyoming

5.41% top marginal rate
Structure
Progressive
Burden @ $100K
$3,181
Selected

16

Idaho

5.51% top marginal rate
Structure
Progressive
Burden @ $100K
$1,742

28

Mississippi

5.92% top marginal rate
Structure
Progressive
Burden @ $100K
$16,823

45

South Carolina

6.10% top marginal rate
Structure
Progressive
Burden @ $100K
$5,396

Bridges Needing Most Attention in Idaho

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

STC 6774;TETON HWY

Poor

Over: S.FK.TETON RIVER

0.5 N. TETON, Fremont, ID

Built 1977 Load: 0.9 t ADT: 1,200

SWAMP ROAD

Poor

Over: CAMAS CREEK

1.5 S. 0.3 E. HILL CITY, Camas, ID

Built 1965 Load: 1.8 t ADT: 40

ROAD 50343

Poor

Over: LOGAN CREEK

NO DATA ENTERED, Valley, ID

Built 1980 Load: 2.6 t ADT: 50

VADNAIS LANE

Poor

Over: CAMAS CREEK

1.9 S. 0.6 E. KILGORE, Clark, ID

Built 1981 Load: 2.7 t ADT: 50

2701: NORTH MILNER

Poor

Over: Milner Gooding Canal

5.0 mi N of Hunt Rd, Jerome, ID

Built 1960 Load: 4.2 t ADT: 25

MIDDLE FORK ROAD

Structurally Deficient

Over: M.FK.WEISER RIVER

7.3 W 3.4 S DONNELLY, Adams, ID

Built 1957 Load: 4.5 t ADT: 70

All Bridges in Idaho

RUBY CREEK RD

Poor

Over: RUBY CREEK(#4)

3.3 N. 0.8 W. NAPLES, Boundary, ID

Built 1970 Load: 30.8 t ADT: 30

FDR 500

Poor

Over: ELDORADO CREEK

32 MILES FROM KAMIAH, ID, Idaho, ID

Built 1967 Load: 31.1 t ADT: 99

FS ROUTE NO. 1221

Poor

Over: GOLD CREEK

GOLD CREEK, Shoshone, ID

Built 1963 Load: 32.4 t ADT: 50

NO DATA ENTERED

Poor

Over: BOULDER CREEK

NO DATA ENTERED, Adams, ID

Built 1957 Load: 32.7 t ADT: 50

FS ROUTE NO. 1009

Poor

Over: GRASS CREEK

GRASS CR, Boundary, ID

Built 1972 Load: 32.7 t ADT: 50

FDR 520

Poor

Over: YOOSA CREEK

27 MILES FROM PIERCE, Idaho, ID

Built 1963 Load: 34.0 t ADT: 40

FS ROUTE NO. 2361

Poor

Over: BEAVER CREEK

JCT W/SHOSHONE CO. RD.456, Shoshone, ID

Built 1983 Load: 34.3 t ADT: 50

NO DATA ENTERED

Poor

Over: BOULDER CREEK

NO DATA ENTERED, Lemhi, ID

Built 1966 Load: 35.3 t ADT: 200

FDR 382

Poor

Over: ELK CREEK

5 MILES FROM ELK RIVER ID, Clearwater, ID

Built 1961 Load: 36.3 t ADT: 20

SALMON RIVER ROAD

Poor

Over: PINE CREEK

PINE CREEK, Lemhi, ID

Built 2012 Load: 37.3 t ADT: 350

NO DATA ENTERED

Poor

Over: OSIER CREEK

2.0 MI N OF OLD KELLY CR, Clearwater, ID

Built 1954 Load: 37.6 t ADT: 40

OR 86 (HWY 012)

Poor

Over: SNAKE RIVER (OXBOW)

ORE-IDAHO STATE LINE, Adams, ID

Built 1961 Load: 38.9 t ADT: 98

OLD CHILLI ROAD

Poor

Over: THOUSAND SPRINGS CREEK

12.6 N. 13.2 W. MACKAY, Custer, ID

Built 1926 Load: 39.9 t ADT: 80

BLUFF ROAD

Poor

Over: BIG WILLOW CREEK

2.1N 2.4E NEW PLYMOUTH, Payette, ID

Built 1962 Load: 40.5 t ADT: 130

IRR BIA RTE 11

Poor

Over: LITTLE HANGMAN CREEK

2.4 KM SOUTH OF AGENCY, Benewah, ID

Built 1977 Load: 49.8 t ADT: 350

STC2714;3700 NORTH

Poor

Over: ROCK CREEK

1.0 S. 0.4 E. TWIN FALLS, Twin Falls, ID

Built 1973 Load: 99.9 t ADT: 6,300

STC 3988;ROSEBERRY

Poor

Over: WILLOW CREEK

1.5 E. DONNELLY, Valley, ID

Built 1996 Load: 99.9 t ADT: 350

FS ROUTE NO. 2450

Structurally Deficient

Over: BLUE JOE CREEK

BLUE JOE CREEK, Boundary, ID

Built 1953 ADT: 50

FS ROUTE NO 2546

Structurally Deficient

Over: BLUE JOE CREEK UPPER

BLUE JOE UPPER, Boundary, ID

Built 1953 ADT: 50

MIDDLE FORK ROAD

Structurally Deficient

Over: M.FK.WEISER RIVER

7.3 W 3.4 S DONNELLY, Adams, ID

Built 1957 Load: 4.5 t ADT: 70

S ANDERSON LAKE RD

Structurally Deficient

Over: CD'A RIVER;SPRINGSTON BR

1.7 N. 2.4 E. HARRISON, Kootenai, ID

Built 1955 Load: 6.3 t ADT: 40

LTL WOOD RES. ROAD

Structurally Deficient

Over: MULDOON CREEK

12.8 N. 2.8 W. CAREY, Blaine, ID

Built 1954 Load: 6.4 t ADT: 30

OLD MIL. RR GRADE

Structurally Deficient

Over: TROUT CREEK

0.9N 3.1W CALDER, Shoshone, ID

Built 1912 Load: 6.4 t ADT: 15

FIFTH STREET

Structurally Deficient

Over: S.FK.COEUR D'ALENE RIVER

IN MULLAN;FIFTH STREET, Shoshone, ID

Built 1972 Load: 9.1 t ADT: 50

JIM BROWN BRIDGE R

Structurally Deficient

Over: LITTLE WOOD RIVER

3.2 N. 3.7 E. RICHFIELD, Lincoln, ID

Built 1965 Load: 13.6 t ADT: 5

FOREST ROAD 357

Structurally Deficient

Over: RUNNING CR

NO DATA ENTERED, Idaho, ID

Built 1956 Load: 14.6 t ADT: 50

FOREST ROAD 421

Structurally Deficient

Over: LITTLE MALLARD CREEK

AT SALMON RIVER, Idaho, ID

Built 1984 Load: 14.6 t ADT: 50

ROARING RIVER ROAD

Structurally Deficient

Over: MIDDLE FORK BOISE RIVER

4.5 MI WSW DUTCH CR CABIN, Elmore, ID

Built 1957 Load: 19.8 t ADT: 20

STC2768;2400 E. RD

Structurally Deficient

Over: MILNER GOODING CANAL

2.5 S. 4.5 E. HAZELTON, Jerome, ID

Built 1970 Load: 19.8 t ADT: 310

FOREST ROAD 651

Structurally Deficient

Over: SELWAY RIVER-OHARA

7 MI. FROM LOWELL, ID, Idaho, ID

Built 1956 Load: 21.7 t ADT: 50

SH 55

Structurally Deficient

Over: UPRR;N.FK.PAYETTE RIVER

3.0 N. SMITHS FERRY, Valley, ID

Built 1933 Load: 21.8 t ADT: 4,200

FDR

Structurally Deficient

Over: VALLEY CREEK

6 MILES NW OF STANLEY, Custer, ID

Built 1950 Load: 24.0 t ADT: 50

STC7151;BENTON ST

Structurally Deficient

Over: PORTNEUF RIVER

IN POCATELLO;BENTON ST, Bannock, ID

Built 1969 Load: 25.4 t ADT: 2,800

FOREST ROAD 1614

Structurally Deficient

Over: FRENCH CREEK

18 MI. FROM RIGGINS, ID, Idaho, ID

Built 1957 Load: 27.9 t ADT: 50

FS ROUTE NO. 427

Structurally Deficient

Over: BOULDER CR CALLAHAN

BOULDER CREEK, Boundary, ID

Built 1961 Load: 30.5 t ADT: 50

RD 360

Structurally Deficient

Over: SAVAGE CREEK

10 MI FROM POWELL RS, Idaho, ID

Built 2006 Load: 31.8 t ADT: 10

BEAVER-LOON ROAD

Structurally Deficient

Over: JORDAN CREEK

NO DATA ENTERED, Custer, ID

Built 1993 Load: 32.7 t ADT: 100

EAST FORK RD

Structurally Deficient

Over: ROAD CREEK

5.8 S 5.6 E CLAYTON, Custer, ID

Built 2022 Load: 33.0 t ADT: 90

FDR 382

Structurally Deficient

Over: ELK CREEK

4 MILES FROM ELK RIVER ID, Clearwater, ID

Built 1961 Load: 36.3 t ADT: 20

CROOKED RIVER ROAD

Structurally Deficient

Over: UPPER CROOKED RIVER

30.2 E 12.6 S GRANGEVILLE, Idaho, ID

Built 1965 Load: 40.8 t ADT: 50

FALL CK.-ROCKY BAR

Structurally Deficient

Over: EAST FORK FALL CREEK

1 MI N.W. OF RED MOUNTAIN, Elmore, ID

Built 2013 Load: 50.2 t ADT: 50

STC 5711;MOON PASS

Structurally Deficient

Over: BIG DICK CREEK

5.6 N. 2.5 E. AVERY, Shoshone, ID

Built 1909 Load: 68.9 t ADT: 360

Showing 1,701-1,742 of 1,742 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.