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

GEORGIA AVE

Good

Over: WILSON DRAIN

IN CALDWELL, Canyon, ID

Built 2005 Load: 36.3 t ADT: 80

ROAD

Good

Over: KAY CREEK

NO DATA ENTERED, Clark, ID

Built 2011 Load: 36.3 t ADT: 24

ROAD

Good

Over: COTTONWOOD CREEK

NO DATA ENTERED, Clark, ID

Built 2011 Load: 36.3 t ADT: 24

OLD HWY 28;BACK RD

Good

Over: AGENCY CREEK

0.4 S. 0.2 E. TENDOY, Lemhi, ID

Built 2012 Load: 36.3 t ADT: 50

4TH OF JULY CR RD

Good

Over: FOURTH OF JULY CREEK

2.0 S 4.0 E NORTH FORK, Lemhi, ID

Built 2013 Load: 36.3 t ADT: 70

FS ROUTE NO. 400

Good

Over: SVEE CREEK

19.5 MI FORM BABINS JCT., Shoshone, ID

Built 1976 Load: 36.3 t ADT: 40

ROAD 216

Good

Over: HOMESTEAD CREEK

SEC 30, T. 44 N., R. 4 E., Shoshone, ID

Built 2018 Load: 36.3 t ADT: 50

NO MAN ROAD

Good

Over: WHITEHAWK CREEK

6 MI ESE DEADWOOD RSRVOIR, Valley, ID

Built 1978 Load: 36.3 t ADT: 10

FALL CREEK ROAD

Good

Over: MIDDLE FK WEISER RIVER

5.9 S 3.1 E COUNCIL, Adams, ID

Built 2022 Load: 36.6 t ADT: 10

US 20

Good

Over: BIG WOOD RIVER

23.9 E. FAIRFIELD, Blaine, ID

Built 2017 Load: 36.6 t ADT: 2,100

I 84 EBL & WBL

Good

Over: UPRR;EAST LATERAL CANAL

AT NAMPA WCL, Canyon, ID

Built 2021 Load: 36.6 t ADT: 96,000

MYRTLE CK. ROAD

Good

Over: FALL CREEK

.5 MI NW ICE SPRING C.G., Elmore, ID

Built 1980 Load: 36.6 t ADT: 10

FOREST ROAD 309

Good

Over: MILL CREEK

1.9 MI. FROM STATE HWY 14, Idaho, ID

Built 2011 Load: 36.6 t ADT: 30

SH 55

Good

Over: N. FK. PAYETTE RIVER

CASCADE NCL, Valley, ID

Built 2015 Load: 36.6 t ADT: 6,000

SH 16

Good

Over: BOISE RIVER

1.3 E. STAR SCL, Ada, ID

Built 2014 Load: 36.9 t ADT: 19,500

FDR 581

Good

Over: TOBOGGAN CREEK

ROAD 581 MP 8.2, Clearwater, ID

Built 2004 Load: 36.9 t ADT: 5

NO DATA ENTERED

Good

Over: NO DATA ENTERED

NO DATA ENTERED, Idaho, ID

Built 2018 Load: 36.9 t ADT: 30

US 95

Good

Over: DEEP CREEK

15.6 N. MOSCOW, Latah, ID

Built 2022 Load: 36.9 t ADT: 5,500

US 95

Good

Over: UPRR;S. EASTPORT OP

1.1 S. EASTPORT, Boundary, ID

Built 2007 Load: 37.2 t ADT: 1,100

I 84 WBL

Good

Over: PHYLLIS CANAL

IN NAMPA, Canyon, ID

Built 2012 Load: 37.2 t ADT: 52,750

FERGUSON LANE

Good

Over: WILLOW CREEEK

1.8 S 2.7 W RIRIE, Bonneville, ID

Built 2014 Load: 37.3 t ADT: 100

SHEEP FARM ROAD

Good

Over: BEAVER CREEK

4.8 N 0.2 W DUBOIS, Clark, ID

Built 2021 Load: 37.3 t ADT: 30

S3837;STRK DAM CTF

Good

Over: MIDDLE LINE CANAL

AT STRIKE DAM, Elmore, ID

Built 1959 Load: 37.3 t ADT: 330

FS ROUTE NO. 209

Good

Over: LAVERNE CREEK

LAVERNE CREEK, Kootenai, ID

Built 1997 Load: 37.3 t ADT: 40

LITTLE WEISER

Good

Over: LITTLE WEISER RIVER

LITTLE WEISER BRIDGE, Adams, ID

Built 2004 Load: 37.6 t ADT: 30

FS ROUTE N0. 1312

Good

Over: MOORES CREEK

MOORES CREEK, Bonner, ID

Built 1980 Load: 37.6 t ADT: 40

E 1300 N

Good

Over: MARYSVILLE CANAL

3.4 E MARYSVILLE, Fremont, ID

Built 2013 Load: 37.6 t ADT: 200

81ST S/COUNTY LINE

Good

Over: GREAT WESTERN CANAL

4.5 S. 6.4 W. IDAHO FALLS, Bonneville, ID

Built 1963 Load: 37.8 t ADT: 80

MULDOON CANYON RD

Good

Over: MULDOON CREEK

21 NE of Carey, Blaine, ID

Built 2021 Load: 37.9 t ADT: 80

OLD SAM OWEN ROAD

Good

Over: THOMPSON PARK BNRR OP

5.3 N. 4.2 W. CLARK FORK, Bonner, ID

Built 2008 Load: 37.9 t ADT: 370

FDR 581

Good

Over: CAYUSE CREEK

14 MILES FROM POWELL R S, Clearwater, ID

Built 1962 Load: 37.9 t ADT: 15

NO DATA ENTERED

Good

Over: CAYUSE CREEK

NO DATA ENTERED, Idaho, ID

Built 2017 Load: 37.9 t ADT: 15

COMPOUND ROAD

Good

Over: SOUTH FORK RED RIVER

RED RIVER R.S. ADMIN SITE, Idaho, ID

Built 1971 Load: 37.9 t ADT: 40

18 MILE ROAD

Good

Over: EIGHTEEN MILE CREEK

5.6 S 4.3 E LEADORE, Lemhi, ID

Built 2020 Load: 37.9 t ADT: 20

1350 EAST ROAD

Good

Over: STRATTON CANAL

2.0 N 1.0 E RICHFIELD, Lincoln, ID

Built 2013 Load: 37.9 t ADT: 112

FS ROUTE 6310

Good

Over: INDEPENDENCE CREEK

4 MI FROM TRAIL CREEK RS., Shoshone, ID

Built 1984 Load: 37.9 t ADT: 40

MANN CK RD 50009

Good

Over: MANN CREEK

NO DATA ENTERED, Washington, ID

Built 1974 Load: 37.9 t ADT: 30

STC2822;GLENDALE R

Good

Over: BIG WOOD RIVER

2.7 S. BELLEVUE, Blaine, ID

Built 1998 Load: 38.1 t ADT: 1,900

I 84 EBL

Good

Over: UPRR

IN NAMPA NCL, Canyon, ID

Built 2011 Load: 38.1 t ADT: 52,750

I 84 WBL

Good

Over: UPRR

IN NAMPA NCL, Canyon, ID

Built 2011 Load: 38.1 t ADT: 52,750

CAN-ADA ROAD

Good

Over: WALDVOGEL CANAL

0.3 S. 0.9 E. MELBA, Canyon, ID

Built 2007 Load: 38.1 t ADT: 300

3700 NORTH

Good

Over: BIG LOST RIVER

1.2 E. DARLINGTON, Custer, ID

Built 2010 Load: 38.1 t ADT: 50

LOLO CREEK ROAD

Good

Over: LOLO CREEK

1.2 S. 4.6 E. WOODLAND, Idaho, ID

Built 1981 Load: 38.1 t ADT: 30

STC 6768;N 4700 E

Good

Over: HARRISON CANAL

0.5 E. 1.2 N. RIRIE, Jefferson, ID

Built 1982 Load: 38.1 t ADT: 1,500

SH 33

Good

Over: CANYON CREEK

8.8 E. NEWDALE, Madison, ID

Built 2006 Load: 38.1 t ADT: 3,400

NO DATA ENTERED

Good

Over: LONG CREEK

60 MI FROM PIERCE ID, Clearwater, ID

Built 1975 Load: 38.2 t ADT: 60

NO DATA ENTERED

Good

Over: LARSON CREEK

13 MI FROM CANYON WC, Clearwater, ID

Built 2011 Load: 38.2 t ADT: 40

MCCORMACK RDG RD

Good

Over: MISSION CREEK

3.5 S. 1.0 W. WINCHESTER, Lewis, ID

Built 2013 Load: 38.2 t ADT: 50

FS ROUTE 1504

Good

Over: SHOSHONE CREEK

SHOSHONE CREEK, Shoshone, ID

Built 1977 Load: 38.2 t ADT: 40

ROAD 492

Good

Over: TEN MILE CREEK

NO DATA ENTERED, Idaho, ID

Built 2012 Load: 38.6 t ADT: 50

Showing 1,401-1,450 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.