State profile · Below median Poor share

Idaho bridge safety

According to the Federal Highway Administration's 2024 National Bridge Inventory, condition ratings, load ratings, and Poor-condition shares for every public highway bridge in Idaho.

4,616
Public bridges
29.5%
Good condition
4.9%
Poor condition

Idaho holds 4,616 public highway bridges (#37 of 52 by inventory) with a 4.9% Poor share (#33 of 52 by Poor share).

That is 4.9% of the state's inventory, against an average of 7.5% across the 54 states and territories with Poor-rated bridges on file, which places it 20 of 54 ordered from the lowest Poor share upward. A bridge is rated Poor when its weakest applicable component scores 4 or below on the inspecting agency's 0-9 scale, so the category is a maintenance and funding signal rather than a closure order or a live crossing-safety verdict.

Inventory: FHWA NBI 2024 · last ETL August 2026

Total Bridges

4,616

Public highway bridges in Idaho

Good Condition

29.5%

1,363 bridges rated 7-9

-20.5pp vs 50% benchmark

Poor Condition

4.9%

226 bridges whose lowest applicable component is rated 0-4

-2.6pp vs national avg 7.5%

Idaho vs national bridge condition

Idaho - Good condition share 29.5%
National avg

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

Idaho - Poor-condition share 16.3%
National avg

Lower is better. Bar maxes at 30% (worst-state ceiling). National average sits at 7.5%.

Idaho in the national condition pattern

Each point is a state or territory in the FHWA NBI; the highlighted point is this profile.

Inventory size and Poor-condition share are different measures: Idaho has 4,616 bridges and a 4.9% Poor-condition share in the 2024 NBI, rank #20 of 54 jurisdictions ordered from the lowest share upward. The dashed comparisons mark the national average state rate and the midpoint of the plotted inventory range; neither is a live safety or closure threshold. Scatter plot of 54 data points. 0%10%20%30%40% 0k20k40k60k Public bridges in inventory (thousands) Poor-condition share (%) ID, Public bridges in inventory (thousands): 4.6k · Poor-condition share (%): 4.9%AL, Public bridges in inventory (thousands): 16.2k · Poor-condition share (%): 3.35%AK, Public bridges in inventory (thousands): 1.7k · Poor-condition share (%): 7.89%AZ, Public bridges in inventory (thousands): 8.6k · Poor-condition share (%): 1.15%AR, Public bridges in inventory (thousands): 13k · Poor-condition share (%): 5.43%CA, Public bridges in inventory (thousands): 25.8k · Poor-condition share (%): 5.91%CO, Public bridges in inventory (thousands): 9k · Poor-condition share (%): 4.82%CT, Public bridges in inventory (thousands): 4.4k · Poor-condition share (%): 4.72%DE, Public bridges in inventory (thousands): 0.9k · Poor-condition share (%): 1.26%DC, Public bridges in inventory (thousands): 0.3k · Poor-condition share (%): 1.95%FL, Public bridges in inventory (thousands): 13k · Poor-condition share (%): 2.79%GA, Public bridges in inventory (thousands): 15.1k · Poor-condition share (%): 1.59%GU, Public bridges in inventory (thousands): 0k · Poor-condition share (%): 12.77%HI, Public bridges in inventory (thousands): 1.2k · Poor-condition share (%): 6.53%IL, Public bridges in inventory (thousands): 26.9k · Poor-condition share (%): 9.35%IN, Public bridges in inventory (thousands): 19.5k · Poor-condition share (%): 5.22%IA, Public bridges in inventory (thousands): 23.7k · Poor-condition share (%): 19.16%KS, Public bridges in inventory (thousands): 24.9k · Poor-condition share (%): 5.26%KY, Public bridges in inventory (thousands): 14.5k · Poor-condition share (%): 7.37%LA, Public bridges in inventory (thousands): 12.7k · Poor-condition share (%): 11.48%ME, Public bridges in inventory (thousands): 2.5k · Poor-condition share (%): 15.41%MD, Public bridges in inventory (thousands): 5.5k · Poor-condition share (%): 4.56%MA, Public bridges in inventory (thousands): 5.3k · Poor-condition share (%): 8.88%MI, Public bridges in inventory (thousands): 11.4k · Poor-condition share (%): 11.27%MN, Public bridges in inventory (thousands): 13.5k · Poor-condition share (%): 4.44%MS, Public bridges in inventory (thousands): 16.7k · Poor-condition share (%): 6.03%MO, Public bridges in inventory (thousands): 24.6k · Poor-condition share (%): 8.95%MT, Public bridges in inventory (thousands): 5.2k · Poor-condition share (%): 6.81%NE, Public bridges in inventory (thousands): 15.4k · Poor-condition share (%): 7.9%NV, Public bridges in inventory (thousands): 2.1k · Poor-condition share (%): 1.14%NH, Public bridges in inventory (thousands): 2.5k · Poor-condition share (%): 7.51%NJ, Public bridges in inventory (thousands): 6.8k · Poor-condition share (%): 6.01%NM, Public bridges in inventory (thousands): 4k · Poor-condition share (%): 4.51%NY, Public bridges in inventory (thousands): 17.6k · Poor-condition share (%): 9.43%NC, Public bridges in inventory (thousands): 19.2k · Poor-condition share (%): 6.76%ND, Public bridges in inventory (thousands): 4.3k · Poor-condition share (%): 10.98%OH, Public bridges in inventory (thousands): 26.7k · Poor-condition share (%): 4.74%OK, Public bridges in inventory (thousands): 22.9k · Poor-condition share (%): 7.7%OR, Public bridges in inventory (thousands): 8.3k · Poor-condition share (%): 4.61%PA, Public bridges in inventory (thousands): 23.3k · Poor-condition share (%): 12.58%PR, Public bridges in inventory (thousands): 2.4k · Poor-condition share (%): 13.92%RI, Public bridges in inventory (thousands): 0.8k · Poor-condition share (%): 15.2%SC, Public bridges in inventory (thousands): 9.5k · Poor-condition share (%): 6.17%SD, Public bridges in inventory (thousands): 5.9k · Poor-condition share (%): 16.36%TN, Public bridges in inventory (thousands): 20.4k · Poor-condition share (%): 4.41%TX, Public bridges in inventory (thousands): 56.7k · Poor-condition share (%): 1.23%UT, Public bridges in inventory (thousands): 3.1k · Poor-condition share (%): 2.91%VT, Public bridges in inventory (thousands): 2.9k · Poor-condition share (%): 2.9%VI, Public bridges in inventory (thousands): 0k · Poor-condition share (%): 29.17%VA, Public bridges in inventory (thousands): 14.1k · Poor-condition share (%): 3.39%WA, Public bridges in inventory (thousands): 8.5k · Poor-condition share (%): 5.45%WV, Public bridges in inventory (thousands): 7.3k · Poor-condition share (%): 18.64%WI, Public bridges in inventory (thousands): 14.4k · Poor-condition share (%): 6.52%WY, Public bridges in inventory (thousands): 3.1k · Poor-condition share (%): 6.51%
Inventory size and Poor-condition share are different measures: Idaho has 4,616 bridges and a 4.9% Poor-condition share in the 2024 NBI, rank #20 of 54 jurisdictions ordered from the lowest share upward. The dashed comparisons mark the national average state rate and the midpoint of the plotted inventory range; neither is a live safety or closure threshold.

Idaho vs all states by public bridge inventory

Where this state's FHWA NBI public-highway bridge count sits among every state and territory on PlainBridges

4,616 37th of 54 higher than 17 of 54 states

States and territories, banded by public bridge inventory size

Each bar is a band; taller bars hold more states. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.

Source FHWA National Bridge Inventory · 2024

Read the rank neighborhood for Idaho

The highlighted point is Idaho: 4,616 bridges and 4.90% in Poor condition, rank #20 of 54 jurisdictions ordered from the lowest share upward. The five jurisdictions immediately above and below Idaho on that same Poor-share ordering:

  • Ohio: 26,729 bridges · 4.74% Poor
  • Colorado: 8,965 bridges · 4.82% Poor
  • Idaho: 4,616 bridges · 4.90% Poor
  • Indiana: 19,495 bridges · 5.22% Poor
  • Kansas: 24,894 bridges · 5.26% Poor

The full national sortable table lives on the rankings page.

Material families in Idaho

Exclusive FHWA material families across all 4,616 bridges in this state; continuous variants fold into the parent family. Orthogonal to the Poor-share scatter above.

Who maintains Idaho’s inventory

State agency holds 29.8% of the 4,616 public highway bridges filed under Idaho in the 2024 NBI, the agency-of-record split for this state, not a condition verdict.

When Idaho’s bridges were built

Pre-1950 construction accounts for 7.0% of the 4,616 bridges with a recorded original year in Idaho. Era bands are orthogonal to the Poor-share ranking above.

Condition Distribution

Idaho29.5%65.6%GoodFairPoor
Bridge inventory deck-condition mix - Idaho (FHWA NBI)

Counties (44)

Ada 299 Adams 87 Bannock 124 Bear Lake 34 Benewah 47 Bingham 263 Blaine 96 Boise 88 Bonner 104 Bonneville 213 Boundary 83 Butte 32 Camas 61 Canyon 292 Caribou 45 Cassia 116 Clark 40 Clearwater 88 Custer 128 Elmore 97 Franklin 23 Fremont 137 Gem 57 Gooding 80 Idaho 215 Jefferson 127 Jerome 110 Kootenai 154 Latah 115 Lemhi 112 Lewis 21 Lincoln 53 Madison 80 Minidoka 66 Nez Perce 71 Oneida 23 Owyhee 48 Payette 65 Power 70 Shoshone 260 Teton 37 Twin Falls 126 Valley 149 Washington 80

Idaho vs nearby ranks

Adjacent states by Poor-condition share (lower share = better)

States are ranked by the share of bridges whose lowest applicable component rating is 4 or below. This describes recorded condition; it does not measure funding effectiveness or live crossing safety. States here sit immediately above and below Idaho on the same metric.

OH

Ohio

4.74% top marginal rate
Structure
Progressive
Burden @ $100K
$26,729

CO

Colorado

4.82% top marginal rate
Structure
Progressive
Burden @ $100K
$8,965
Selected

ID

Idaho

4.90% top marginal rate
Structure
Progressive
Burden @ $100K
$4,616

IN

Indiana

5.22% top marginal rate
Structure
Progressive
Burden @ $100K
$19,495

KS

Kansas

5.26% top marginal rate
Structure
Progressive
Burden @ $100K
$24,894

Bridges Needing Most Attention in Idaho

Six lowest-condition bridges in Idaho, ranked by the portal's composite display score. Inspection intervals are risk-based under current NBIS rules.

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

RIVER ROAD

Poor

Over: VINSON WASH

2.0 N. 2.6 W. GRAND VIEW, Owyhee, ID

Built 1930 Load: 0.9 t ADT: 60

SWAMP ROAD

Poor

Over: CAMAS CREEK

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

Built 1965 Load: 1.8 t ADT: 40

ELK SUMMIT RD

Poor

Over: SOUTH FORK SALMON RIVER

14.6 N 4.3 W YELLOW PINE, Valley, ID

Built 1934 Load: 1.8 t ADT: 10

ROAD 50343

Poor

Over: LOGAN CREEK

NO DATA ENTERED, Valley, ID

Built 1980 Load: 2.6 t ADT: 50

200 SOUTH ROAD

Poor

Over: CAMAS CREEK

1.9 S. 6.8 E. FAIRFIELD, Camas, ID

Built 1920 Load: 2.7 t ADT: 30

All Bridges in Idaho

SH 46

Good

Over: CEDAR DRAW CANAL

5.0 S 1.8 W WENDELL SCL, Gooding, ID

Built 2016 Load: 34.0 t ADT: 3,800

FS ROUTE 612

Good

Over: N.F. CDA RIVER

18 MI FROM CDA IDAHO, Kootenai, ID

Built 1976 Load: 34.0 t ADT: 40

FDR 103

Good

Over: MIDDLE CREEK

24 MI NORTH OF FDR 100, Idaho, ID

Built 1973 Load: 34.0 t ADT: 5

SH 36

Good

Over: MINK CREEK

8.6 E. SH 34/SH 36 JCT, Franklin, ID

Built 2015 Load: 34.3 t ADT: 430

STP 9183;TEN MILE

Good

Over: I 84; TEN MILE RD IC

2.0 W. MERIDIAN, Ada, ID

Built 2011 Load: 34.3 t ADT: 20,000

MISSION CREEK ROAD

Good

Over: MISSION CREEK

1.0 S. JACQUES SPUR, Nez Perce, ID

Built 2016 Load: 34.3 t ADT: 170

ROSS FORK RD

Good

Over: I 15 NB-SB; FORT HALL IC

1.5 SE FORT HALL, Bannock, ID

Built 2023 Load: 34.3 t ADT: 1,100

E 100 N

Good

Over: WILLOW CREEK

0.6 N. 12.3 E. FAIRFIELD, Camas, ID

Built 2019 Load: 34.3 t ADT: 20

STC 3826;ALDER CRK

Good

Over: S.FK.PAYETTE RIVER

1.2 S.E. GARDEN VALLEY, Boise, ID

Built 2014 Load: 34.3 t ADT: 450

STC5907;DEEP CRK

Good

Over: DEEP CREEK

1.5 N 0.3 W NAPLES, Boundary, ID

Built 2014 Load: 34.3 t ADT: 360

ESTHER SIMPLOT PK

Good

Over: ESTHERS POND

IN ESTHER SIMPLOT PARK, Ada, ID

Built 2016 Load: 34.3 t ADT: 80

GYPSY BAY ROAD

Good

Over: GYPSY CREEK

2.8 N. 7.7 W. SAGLE, Bonner, ID

Built 2020 Load: 34.3 t ADT: 30

NO DATA ENTERED

Good

Over: WYLIE CREEK

NO DATA ENTERED, Bonner, ID

Built 2014 Load: 34.3 t ADT: 40

FOREST ROAD 440A

Good

Over: WEST FORK NEWSOME CREEK

NEWSOME CREEK DRAINAGE, Idaho, ID

Built 2019 Load: 34.3 t ADT: 50

I 86 EBL

Good

Over: KOPP ROAD GS

2.7 E. AMERICAN FALLS, Power, ID

Built 1959 Load: 34.5 t ADT: 6,250

I 86 WBL

Good

Over: KOPP ROAD GS

2.7 E. AMERICAN FALLS, Power, ID

Built 1959 Load: 34.5 t ADT: 6,250

I 86 EBL

Good

Over: LEYSHON ROAD GS

3.9 E. AMERICAN FALLS, Power, ID

Built 1959 Load: 34.5 t ADT: 6,250

I 86 WBL

Good

Over: LEYSHON ROAD GS

3.9 E. AMERICAN FALLS, Power, ID

Built 1959 Load: 34.5 t ADT: 6,250

I 15 NBL

Good

Over: STP 7341; CENTER ST. IC.

IN POCATELLO, Bannock, ID

Built 2007 Load: 34.5 t ADT: 13,000

I 15 SBL

Good

Over: SIDEHILL CANAL

2.7 S. IDAHO FALLS, Bonneville, ID

Built 1962 Load: 34.5 t ADT: 14,250

I 15 NBL

Good

Over: SIDEHILL CANAL

2.7 S. IDAHO FALLS, Bonneville, ID

Built 1962 Load: 34.5 t ADT: 14,250

US 20 WBL & EBL

Good

Over: N.BR.FALL RIVER CANAL

2.0 E. ST ANTHONY, Fremont, ID

Built 1979 Load: 34.5 t ADT: 9,000

SH 55

Good

Over: BOISE RIVER;N.CHANNEL

0.7 S. EAGLE, Ada, ID

Built 1978 Load: 34.5 t ADT: 40,500

STC3906;WARREN WGN

Good

Over: TWENTY MILE CREEK

15.7 N. 4.0 E. MCCALL, Valley, ID

Built 1969 Load: 34.5 t ADT: 530

STC 4719;RED RIVER

Good

Over: SIEGEL CREEK

3.8 S. 2.4 E. ELK CITY, Idaho, ID

Built 1964 Load: 34.5 t ADT: 150

N 300 W

Good

Over: S CHANNEL SPRING CREEK

0.4 S. TETONIA, Teton, ID

Built 1967 Load: 34.5 t ADT: 310

2-1/2 MILE ROAD

Good

Over: FORT HALL MAIN CANAL

2.4 N 1.0 E CHUBBUCK, Bannock, ID

Built 2011 Load: 34.5 t ADT: 500

PARIS BOTTOMS ROAD

Good

Over: BEAR LAKE OUTLET CANAL

0.4 N. 2.3 E. PARIS, Bear Lake, ID

Built 2009 Load: 34.5 t ADT: 190

3900 NORTH RD

Good

Over: LOW LINE CANAL

2.4 S. 0.4 E. BUHL, Twin Falls, ID

Built 1965 Load: 34.5 t ADT: 80

HUBBARD ROAD

Good

Over: LITTLE SALMON RIVER

0.8 W. NEW MEADOWS, Adams, ID

Built 2004 Load: 34.5 t ADT: 20

FARNER ROAD

Good

Over: MORA CANAL

3.5 S. 6.6 W. NAMPA, Canyon, ID

Built 2003 Load: 34.5 t ADT: 50

S. 11TH AVENUE

Good

Over: INDIAN CREEK

IN CALDWELL; 11TH AVE, Canyon, ID

Built 2009 Load: 34.5 t ADT: 968

FRONT STREET

Good

Over: I 84B;NAMPA 11TH AVE UP

IN NAMPA;FRONT ST., Canyon, ID

Built 2003 Load: 34.5 t ADT: 22,500

WHITE BIRD RIDGE

Good

Over: LITTLE SALMON RIVER

2.6 S. POLLOCK, Idaho, ID

Built 2004 Load: 34.5 t ADT: 100

TALL PINES ROAD

Good

Over: DAWSON CREEK

6 S. 5 W. COEUR DALENE, Kootenai, ID

Built 2009 Load: 34.5 t ADT: 220

3000 EAST ROAD

Good

Over: BADGER CREEK

3.3 N TETONIA, Teton, ID

Built 2013 Load: 34.5 t ADT: 100

STC4747;BIG CANYON

Good

Over: BEAR CREEK

AT PECK NCL, Nez Perce, ID

Built 2019 Load: 34.7 t ADT: 500

STC5750;PINE CREEK

Good

Over: PINE CREEK

1.3 S. PINEHURST, Shoshone, ID

Built 2019 Load: 34.7 t ADT: 850

720 NORTH ROAD

Good

Over: MILNER GOODING CANAL

7.2 N. 7.7 W SHOSHONE, Lincoln, ID

Built 2021 Load: 34.7 t ADT: 50

S6869;FSH HATCHRY

Good

Over: BIG LOST RIVER(PENCE BR)

5.4 N. 7.6 W. MACKAY, Custer, ID

Built 2018 Load: 34.7 t ADT: 160

SH 39

Good

Over: PEOPLES CANAL

8.0 W. BLACKFOOT, Bingham, ID

Built 2018 Load: 35.0 t ADT: 5,000

SH 46

Good

Over: BIG WOOD RIVER

1.0 N. GOODING, Gooding, ID

Built 2022 Load: 35.0 t ADT: 3,400

SH 52

Good

Over: IN&P RR

11.0 E. PAYETTE, Payette, ID

Built 2018 Load: 35.0 t ADT: 1,700

SH 75

Good

Over: E. FK. SALMON RIVER

5.1 E. CLAYTON, Custer, ID

Built 2014 Load: 35.0 t ADT: 590

US 95

Good

Over: ROBERTSON SLOUGH

0.6 S. WEISER SCL, Washington, ID

Built 2017 Load: 35.0 t ADT: 7,600

SMA 7841;A STREET

Good

Over: B CANAL

IN RUPERT, Minidoka, ID

Built 2014 Load: 35.0 t ADT: 3,100

STC4702;SALMON RVR

Good

Over: SALMON RVR (MANNING CRV)

9.6 E. 1.3 S. RIGGINS, Idaho, ID

Built 2018 Load: 35.0 t ADT: 250

MCGARY GRADE ROAD

Good

Over: POTLACH RIVER

0.8 N. 1.0 E. JULIAETTA, Nez Perce, ID

Built 2016 Load: 35.0 t ADT: 110

STC5907;DEEP CREEK

Good

Over: DEEP CREEK #4

4.1 N 0.3 E. NAPLES, Boundary, ID

Built 2012 Load: 35.0 t ADT: 360

E. STAGE COACH RD

Good

Over: EAST MADDEN LATERAL

4.5 N 1.4 W Melba, Canyon, ID

Built 2019 Load: 35.0 t ADT: 200

Showing 3,551-3,600 of 4,616 bridges

Related

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

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). Poor condition is an inspection-record category, not a closure or unsafe-to-cross designation. Consult the bridge owner for current status.

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.

What to do with this

Use Idaho's inventory picture to drill to a county or a specific span.

NBI condition ratings are inventory snapshots, not live crossing-safety verdicts.

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Idaho Good/Fair/Poor shares and county rollups on this page are computed from the same NBI extract as the national boards; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.