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 4

Good

Over: CANYON CREEK;LOWER MACE

1.2 S. BURKE, Shoshone, ID

Built 2004 Load: 45.4 t ADT: 190

US 12

Good

Over: GLADE CREEK

8.9 E. LOWELL, Idaho, ID

Built 2010 Load: 45.4 t ADT: 530

SH 34

Good

Over: TINCUP CREEK

14.8 E. WAYAN, Caribou, ID

Built 2018 Load: 45.4 t ADT: 540

SH 55

Good

Over: I 84;KARCHER-MIDLAND IC

IN NAMPA, Canyon, ID

Built 2006 Load: 45.4 t ADT: 35,000

SH 69

Good

Over: TEED LATERAL CANAL

8.0 S. MERIDIAN, Ada, ID

Built 1990 Load: 45.4 t ADT: 14,000

I 84 WBL & EBL

Good

Over: I 84B ;GARRITY BLVD IC

AT NAMPA ECL, Canyon, ID

Built 2011 Load: 45.4 t ADT: 105,500

US 2

Good

Over: SAND CREEK

AT PONDERAY SWCL, Bonner, ID

Built 1973 Load: 45.4 t ADT: 18,500

I 15B;SUNNYSIDE RD

Good

Over: I 15;SUNNYSIDE RD IC

1.1 W. IDAHO FALLS, Bonneville, ID

Built 2007 Load: 45.4 t ADT: 10,500

STP 7933;21ST AVE

Good

Over: INDIAN CREEK

IN CALDWELL;21ST AVE, Canyon, ID

Built 2009 Load: 45.4 t ADT: 15,000

12TH STREET

Good

Over: PORTNEUF RIVER

0.1 S 0.6 E MCCAMMON, Bannock, ID

Built 2005 Load: 45.4 t ADT: 108

BETHEL STREET

Good

Over: RIDENBAUGH CANAL

IN BOISE, Ada, ID

Built 1998 Load: 45.4 t ADT: 1,000

FARRELL ROAD

Good

Over: W.BR.GOOSE CREEK

0.5 E. NEW MEADOWS, Adams, ID

Built 1991 Load: 45.4 t ADT: 80

KEITHLY CREEK ROAD

Good

Over: KEITHLY CREEK

2.5 N. 1.1 W. MIDVALE, Washington, ID

Built 1995 Load: 45.4 t ADT: 30

HARMONY HEIGHTS RD

Good

Over: OROFINO CREEK

0.4 S. 3.7 E. OROFINO, Clearwater, ID

Built 2020 Load: 45.4 t ADT: 220

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

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

S. FINDLEY AVENUE

Good

Over: NEW YORK CANAL

IN BOISE, Ada, ID

Built 1998 Load: 45.4 t ADT: 400

STP7243;E PARK CTR

Good

Over: WALLING DITCH

EAST BOISE, Ada, ID

Built 2009 Load: 45.4 t ADT: 9,600

650 EAST ROAD

Good

Over: H CANAL

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

Built 2022 Load: 45.7 t ADT: 90

SH 3

Good

Over: W. FK. POTLATCH RIVER

3.5 N. BOVILL, Latah, ID

Built 2020 Load: 46.0 t ADT: 440

US 95

Good

Over: LITTLE SALMON RIVER

15.4 N. NEW MEADOWS NCL, Idaho, ID

Built 2017 Load: 46.0 t ADT: 2,500

SH 16

Good

Over: W.JOPLIN CT;EUREKA CANAL

0.8 S 1.25 E STAR SCL, Ada, ID

Built 2014 Load: 46.0 t ADT: 19,500

FS ROUTE NO. 400

Good

Over: SVEE CREEK

19.4 MI FROM BABINS JCT., Shoshone, ID

Built 1976 Load: 46.0 t ADT: 40

I 86 WBL

Good

Over: HILINE ROAD GS

0.8 E. CHUBBUCK, Bannock, ID

Built 2010 Load: 46.3 t ADT: 12,750

US 30

Good

Over: PORTNEUF RIVER

1.9 W. LAVA HOT SPRINGS, Bannock, ID

Built 2008 Load: 46.3 t ADT: 5,800

I 84 EBL

Good

Over: D LINE CANAL

9.1 W. CALDWELL, Payette, ID

Built 1961 Load: 46.3 t ADT: 15,000

US 89

Good

Over: OVID CREEK

3.77 N. PARIS, Bear Lake, ID

Built 2019 Load: 46.3 t ADT: 2,000

SH 75

Good

Over: MALM GULCH

12.1 S. CHALLIS, Custer, ID

Built 1988 Load: 46.3 t ADT: 590

US 95

Good

Over: MISSION CREEK

3.2 N. CULDESAC, Nez Perce, ID

Built 1997 Load: 46.3 t ADT: 3,500

SH 97

Good

Over: WOLF LODGE CREEK

27.4 N. HARRISON, Kootenai, ID

Built 2005 Load: 46.3 t ADT: 3,100

STC 6770;SALEM RD

Good

Over: INDEPENDENT CANAL

0.9 S 1.0 W PARKER, Fremont, ID

Built 2011 Load: 46.3 t ADT: 1,400

STC 7819;KINGS RD

Good

Over: UPRR;KINGS RD OP

IN NAMPA;KINGS RD., Canyon, ID

Built 2006 Load: 46.3 t ADT: 10,500

MORMON ROAD

Good

Over: W. FORK SOLDIER CREEK

2.2 S FAIRFIELD, Camas, ID

Built 2022 Load: 46.3 t ADT: 110

MOSS LANE

Good

Over: PHYLLIS CANAL

IN CALDWELL, Canyon, ID

Built 2005 Load: 46.3 t ADT: 1,700

STC3753;LONE STAR

Good

Over: CALDWELL CANAL

6.0 S 1.4 E CALDWELL, Canyon, ID

Built 2010 Load: 46.3 t ADT: 710

JOHNSON LANE

Good

Over: INDIAN CREEK

AT CALDWELL NCL, Canyon, ID

Built 2001 Load: 46.3 t ADT: 300

PHIFER CREEK ROAD

Good

Over: M.FK.BOISE RIVER

0.9 N. 11.3 W. ATLANTA, Elmore, ID

Built 1968 Load: 46.3 t ADT: 30

ROUND VALLEY RD

Good

Over: ROUND VALLEY CREEK

2.3 N. 2.7 E.SMITHS FERRY, Valley, ID

Built 1992 Load: 46.3 t ADT: 100

SHEEP STATION ROAD

Good

Over: I 15;SHEEP STATION RD IC

5.0 N. DUBOIS, Clark, ID

Built 1990 Load: 46.3 t ADT: 30

SH 14

Good

Over: LEGGETT CREEK

4.8 E. GOLDEN, Idaho, ID

Built 2018 Load: 46.7 t ADT: 150

US 95

Good

Over: WILDLIFE CROSSING

3.5 S. ATHOL, Kootenai, ID

Built 2012 Load: 46.7 t ADT: 9,500

OLD RIVER ROAD

Good

Over: LITTLE N.FK.CDA RIVER

3.4 N. 0.4 E. ENAVILLE, Shoshone, ID

Built 1985 Load: 46.8 t ADT: 100

SH 25

Good

Over: N CANAL

1.0 W. JEROME, Jerome, ID

Built 2021 Load: 47.0 t ADT: 10,500

US 26

Good

Over: PEOPLES CANAL

5.4 W. BLACKFOOT, Bingham, ID

Built 2018 Load: 47.0 t ADT: 3,100

SH 28

Good

Over: LEMHI RIVER

18.5 N. LEADORE., Lemhi, ID

Built 2019 Load: 47.0 t ADT: 820

US 91

Good

Over: SNAKE RIVER VALLEY CANAL

1.9 N. SHELLY, Bingham, ID

Built 2018 Load: 47.0 t ADT: 9,300

SWAMP ROAD

Good

Over: MONUMENT GULCH CREEK

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

Built 2022 Load: 47.0 t ADT: 40

I 15 NBL

Good

Over: SMA 5697;SOUTH VALLEY RD

3.35 SE POCATELLO, Bannock, ID

Built 2015 Load: 47.0 t ADT: 9,750

I 15 SBL

Good

Over: SMA 5697;SOUTH VALLEY RD

3.35 SE. POCATELLO, Bannock, ID

Built 2015 Load: 47.0 t ADT: 10,000

SH 33

Good

Over: TRAIL CREEK

3.5 E. VICTOR, Teton, ID

Built 2010 Load: 47.2 t ADT: 7,200

Showing 4,051-4,100 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.