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

FS ROUTE NO. 805

Good

Over: WEST FORK EAGLE CREEK

WEST FORK EAGLE CREEK, Shoshone, ID

Built 1957 Load: 41.1 t ADT: 50

NFSR 421

Good

Over: FAWN CREEK

6 MI S. OF LAKE CASCADE, Valley, ID

Built 2011 Load: 41.1 t ADT: 10

EDNA CK.-L.OWL RD.

Good

Over: PIKES FORK CREEK

3 MI ENE OF EDNA CR CG, Boise, ID

Built 2005 Load: 41.5 t ADT: 50

SH 200

Good

Over: TRESTLE CREEK

3.0 W. HOPE, Bonner, ID

Built 2013 Load: 41.5 t ADT: 3,400

US 95

Good

Over: LAPWAI CREEK

1.6 N. 1.0 E. WINCHESTER, Lewis, ID

Built 2019 Load: 41.5 t ADT: 3,500

I 90B LOOP

Good

Over: S.FK.COEUR D'ALENE RIVER

IN MULLAN, Shoshone, ID

Built 2014 Load: 41.5 t ADT: 990

DITCH CREEK RD

Good

Over: DITCH CREEK

10 MI NE OF WARM LAKE, Valley, ID

Built 2009 Load: 41.5 t ADT: 50

S FK OF SALMON RIV

Good

Over: MORMON CREEK

5 MI S OF STOLLE MEADOWS, Valley, ID

Built 2011 Load: 41.5 t ADT: 12

PARADISE VALLEY RO

Good

Over: CABIN CREEK

1 MI N OF WARM LAKE, Valley, ID

Built 2013 Load: 41.5 t ADT: 20

W. CAMAS CREEK RD

Good

Over: W. CAMAS CREEK

7.2 NW. KILGORE, Clark, ID

Built 1970 Load: 41.7 t ADT: 110

3800 NORTH RD

Good

Over: BIG LOST RIVER

1.0 N. DARLINGTON, Custer, ID

Built 2007 Load: 41.7 t ADT: 30

STC 3888;MILL ROAD

Good

Over: WEISER RIVER

0.5N 1.7E CAMBRIDGE, Washington, ID

Built 2002 Load: 41.7 t ADT: 300

IRR BIA RTE 91

Good

Over: BLACKFOOT RIVER

5 KM SW OF BLACKFOOT, Bingham, ID

Built 2015 Load: 41.8 t ADT: 85

HUNTER CK-CRKD. R.

Good

Over: BEAR RIVER

3 MI N.W. OF DEER PARK, Boise, ID

Built 1965 Load: 41.8 t ADT: 12

FS ROUTE 281

Good

Over: COW CREEK

8.6 MI FROM FH.18 JCT., Boundary, ID

Built 1984 Load: 41.8 t ADT: 40

NO DATA ENTERED

Good

Over: OROGRANDE CREEK

OROGRANDE CREEK 1, Clearwater, ID

Built 1956 Load: 41.8 t ADT: 145

BACK RD; OLD LEMHI

Good

Over: PRATT CREEK (#1)

9.0 E. 6.5 S. SALMON, Lemhi, ID

Built 2018 Load: 42.1 t ADT: 50

NO DATA ENTERED

Good

Over: TEAKWEH CREEK

NO DATA ENTERED, Clearwater, ID

Built 2005 Load: 42.4 t ADT: 100

MAYFIELD ROAD

Good

Over: CANYON CREEK

8.8N 0.5W MOUNTAIN HOME, Elmore, ID

Built 2011 Load: 42.6 t ADT: 30

SH 39 NBL

Good

Over: SNAKE R.;AM.FALLS DAM BR

1.1 W. AMERICAN FALLS, Power, ID

Built 1978 Load: 42.6 t ADT: 1,400

US 95

Good

Over: GALLOWAY CANAL

0.4 N. WEISER NCL, Washington, ID

Built 1999 Load: 42.6 t ADT: 5,800

OLD MALAD HWY

Good

Over: MARSH CREEK

2.0 S. 2.0 W. DOWNEY, Bannock, ID

Built 2018 Load: 42.8 t ADT: 330

STC 5804;WESTSIDE

Good

Over: TROUT CREEK

5.0 S. 2.3 W. COPELAND, Boundary, ID

Built 2020 Load: 42.8 t ADT: 300

NO DATA ENTERED

Good

Over: NO DATA ENTERED

NO DATA ENTERED, Latah, ID

Built 2017 Load: 42.8 t ADT: 50

ROAD

Good

Over: LITTLE PINE CREEK

NO DATA ENTERED, Teton, ID

Built 1999 Load: 42.8 t ADT: 10

FS ROUTE NO. 201

Good

Over: E FK FISHHOOK CREEK

E FK FISHHOOK, Shoshone, ID

Built 1967 Load: 43.1 t ADT: 40

FDR

Good

Over: COPPER CREEK

21 MILES EAST OF GIMLET, Blaine, ID

Built 2002 Load: 43.4 t ADT: 50

THUNDER MT RD

Good

Over: TRAPPER CREEK

4.5 MI SW RIORDAN LAKE, Valley, ID

Built 2009 Load: 43.4 t ADT: 50

SH 21

Good

Over: MORES CR;MCKINLEY GULCH

5.9 S. IDAHO CITY, Boise, ID

Built 1990 Load: 43.5 t ADT: 2,000

US 95

Good

Over: BNRR;WESTMOND BRIDGE

1.0 N. WESTMOND, Bonner, ID

Built 2004 Load: 43.5 t ADT: 11,500

US95 SB OFF RAMP

Good

Over: SAND CREEK

IN SANDPOINT, Bonner, ID

Built 2012 Load: 43.5 t ADT: 7,000

SH 47

Good

Over: ROBISON CREEK

8.5 E. ASHTON, Fremont, ID

Built 1984 Load: 43.5 t ADT: 660

US 95 NBL

Good

Over: BELLGROVE CREEK

14.1 S. COEUR D' ALENE, Kootenai, ID

Built 2003 Load: 43.5 t ADT: 4,150

STC2869;400 W. RD.

Good

Over: C CANAL

2.0 E 0.8 N PAUL, Minidoka, ID

Built 2007 Load: 43.5 t ADT: 950

SPRING CREEK WAY

Good

Over: DRY CREEK

DRY CREEK RANCH, Ada, ID

Built 2021 Load: 43.7 t ADT: 130

ROAD

Good

Over: TIE CANYON CREEK

NO DATA ENTERED, Bonneville, ID

Built 1999 Load: 43.7 t ADT: 24

ROAD

Good

Over: COTTONWOOD CREEK

NO DATA ENTERED, Clark, ID

Built 2001 Load: 43.7 t ADT: 50

STP7220;STATE ST

Good

Over: FARMERS UNION CANAL

IN BOISE @ COLLISTER, Ada, ID

Built 2019 Load: 44.1 t ADT: 34,000

SH 28

Good

Over: LEMHI RIVER

19.6 N. LEADORE., Lemhi, ID

Built 2019 Load: 44.1 t ADT: 820

EAGLE NEST-GOLD FK

Good

Over: GOLD FORK RIVER

12 MI WEST OF WARM LAKE, Valley, ID

Built 1967 Load: 44.4 t ADT: 15

E 500 N

Good

Over: ST. ANTHONY CANAL

0.1 S. 2.6 W. PARKER, Fremont, ID

Built 2010 Load: 44.5 t ADT: 280

N 2100 E

Good

Over: EGIN CANAL

1.0 E. PARKER, Fremont, ID

Built 2010 Load: 44.5 t ADT: 150

US 95 NBL

Good

Over: N.FK. ROCK CREEK

3.6 N. WORLEY, Kootenai, ID

Built 2008 Load: 44.5 t ADT: 3,050

LEMHI ROAD

Good

Over: LEMHI RIVER (ALLEN BR)

0.3 S. 0.8 E. SALMON, Lemhi, ID

Built 2016 Load: 45.0 t ADT: 860

BETHEL STREET

Good

Over: RIDENBAUGH CANAL

IN BOISE, Ada, ID

Built 1998 Load: 45.4 t ADT: 1,000

HARMONY HEIGHTS RD

Good

Over: OROFINO CREEK

0.4 S. 3.7 E. OROFINO, Clearwater, ID

Built 2020 Load: 45.4 t ADT: 220

STC6868;TRAIL CRK

Good

Over: N. FORK BIG LOST RIVER

20.5 N.E. SUN VALLEY, Custer, ID

Built 2016 Load: 45.4 t ADT: 290

E 400 N

Good

Over: FARMERS FRIEND CANAL

1.3 S. 0.5 E. ST ANTHONY, Fremont, ID

Built 2009 Load: 45.4 t ADT: 500

KEITHLY CREEK ROAD

Good

Over: KEITHLY CREEK

2.5 N. 1.1 W. MIDVALE, Washington, ID

Built 1995 Load: 45.4 t ADT: 30

650 EAST ROAD

Good

Over: 'H' CANAL

3.7S 2.0W DECLO;450S-650E, Cassia, ID

Built 2022 Load: 45.7 t ADT: 90

Showing 1,501-1,550 of 1,742 bridges

Related

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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.