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

US 20 EBL

Good

Over: US 20B;LEWISVILLE RD IC

ID FALLS;LEWISVILLE HWY, Bonneville, ID

Built 1987 Load: 43.5 t ADT: 11,250

US 20 WBL

Good

Over: US 20B;LEWISVILLE RD IC

ID FALLS;LEWISVILLE HWY, Bonneville, ID

Built 1987 Load: 43.5 t ADT: 11,250

SH 21

Good

Over: MORES CR;MCKINLEY GULCH

5.9 S. IDAHO CITY, Boise, ID

Built 1990 Load: 43.5 t ADT: 2,000

SH 33

Good

Over: TETON RIVER

4.5 NW TETONIA, Teton, ID

Built 1987 Load: 43.5 t ADT: 3,400

SH 47

Good

Over: ROBISON CREEK

8.5 E. ASHTON, Fremont, ID

Built 1984 Load: 43.5 t ADT: 660

US 89

Good

Over: THOMAS FORK CREEK

2.6 N. GENEVA, Bear Lake, ID

Built 1993 Load: 43.5 t ADT: 1,200

US 95 NBL

Good

Over: BELLGROVE CREEK

14.1 S. COEUR D ALENE, Kootenai, ID

Built 2003 Load: 43.5 t ADT: 4,150

US 95 SBL

Good

Over: BELLGROVE CREEK

14.1 S COEUR D ALENE, Kootenai, ID

Built 2002 Load: 43.5 t ADT: 4,150

US 95

Good

Over: BNRR;WESTMOND BRIDGE

1.0 N. WESTMOND, Bonner, ID

Built 2004 Load: 43.5 t ADT: 11,500

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

VIOLA MAIN STREET

Good

Over: FOUR MILE CREEK

0.1 N. VIOLA, Latah, ID

Built 2010 Load: 43.5 t ADT: 130

6TH STREET

Good

Over: LAPWAI CREEK

IN CULDESAC;6TH ST., Nez Perce, ID

Built 1999 Load: 43.5 t ADT: 588

US95 SB OFF RAMP

Good

Over: SAND CREEK

IN SANDPOINT, Bonner, ID

Built 2012 Load: 43.5 t ADT: 7,000

US 20;BROADWAY

Good

Over: I 84 EB-WB;BROADWAY IC

BOISE SCL, Ada, ID

Built 2015 Load: 43.7 t ADT: 32,000

US 95

Good

Over: MUD CREEK

3.3 W. NEW MEADOWS WCL, Adams, ID

Built 2017 Load: 43.7 t ADT: 2,600

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

SH 28

Good

Over: LEMHI RIVER

19.6 N. LEADORE., Lemhi, ID

Built 2019 Load: 44.1 t ADT: 820

SH 53

Good

Over: UPRR

3.7 E. RATHDRUM, Kootenai, ID

Built 2020 Load: 44.1 t ADT: 7,600

LONGHURST LANE

Good

Over: CEDAR POINT CANAL

IN SHELLEY, Bingham, ID

Built 1987 Load: 44.1 t ADT: 100

E 1300 N

Good

Over: HENRYS FK SNAKE RIVER

2.7 W ASHTON, Fremont, ID

Built 2020 Load: 44.1 t ADT: 490

STP7220;STATE ST

Good

Over: FARMERS UNION CANAL

IN BOISE @ COLLISTER, Ada, ID

Built 2019 Load: 44.1 t ADT: 34,000

LEWIS STREET

Good

Over: PORTNEUF RIVER

IN POCATELLO; LEWIS ST, Bannock, ID

Built 2017 Load: 44.1 t ADT: 2,500

FAIRVIEW RD

Good

Over: WASTEWAY CANAL

3.5N 1.8W AMERICAN FALLS, Power, ID

Built 2021 Load: 44.1 t ADT: 25

STC3906;WARREN WGN

Good

Over: DEAD HORSE CREEK

4.9 N MCCALL, Valley, ID

Built 2013 Load: 44.4 t ADT: 530

SNARR RD; W 33RD N

Good

Over: GREAT WESTERN CANAL

2.4 N 2.8 W IDAHO FALLS, Bonneville, ID

Built 2021 Load: 44.4 t ADT: 130

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

US 12

Good

Over: BIG CANYON CREEK

5.9 W. OROFINO, Nez Perce, ID

Built 1984 Load: 44.5 t ADT: 3,300

SH 21

Good

Over: MORES CR.;STIERMAN GULCH

8.3 S. IDAHO CITY, Boise, ID

Built 1990 Load: 44.5 t ADT: 2,000

US 30

Good

Over: PORTNEUF RIVER

6.8 W. LAVA HOT SPRINGS, Bannock, ID

Built 2011 Load: 44.5 t ADT: 5,800

SH 75

Good

Over: BRADSHAW CREEK

14.1 S. CHALLIS, Custer, ID

Built 1988 Load: 44.5 t ADT: 590

I 184B EBL & WBL

Good

Over: S7403;UPRR;FRANKLIN IC

1.0 W. BOISE, Ada, ID

Built 2001 Load: 44.5 t ADT: 73,500

STC3892;INDIAN VLY

Good

Over: LITTLE WEISER RIVER

1.2S INDIAN VALLEY, Adams, ID

Built 2002 Load: 44.5 t ADT: 130

LICK CREEK ROAD

Good

Over: HUM CREEK

14.3 NE MCCALL, Valley, ID

Built 1954 Load: 44.5 t ADT: 40

SMA 8683;BLACK CAT

Good

Over: I 84; BLACK CAT RD GS

3.3 W. MERIDIAN, Ada, ID

Built 2009 Load: 44.5 t ADT: 4,500

STC3730;MARSING RD

Good

Over: MORA CANAL

2.2 S 9.0 W NAMPA, Canyon, ID

Built 2004 Load: 44.5 t ADT: 970

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

US 95 SBL

Good

Over: LAKE CREEK;NESS ROAD

8.0 N. WORLEY, Kootenai, ID

Built 2007 Load: 44.5 t ADT: 2,900

US 12

Good

Over: FISH CREEK

23.5 E. LOWELL, Idaho, ID

Built 2018 Load: 44.7 t ADT: 530

I 86 WBL

Good

Over: RAFT RIVER

28.1 E. BURLEY, Cassia, ID

Built 2019 Load: 44.7 t ADT: 3,850

SH 28

Good

Over: LEMHI RIVER

13.5 N. LEADORE, Lemhi, ID

Built 2018 Load: 44.7 t ADT: 820

SH 28

Good

Over: LEMHI RIVER

0.6 N. TENDOY, Lemhi, ID

Built 2018 Load: 44.7 t ADT: 820

US 89

Good

Over: OVID CREEK

4.9 W. MONTPELIER, Bear Lake, ID

Built 2014 Load: 44.7 t ADT: 3,000

US 95

Good

Over: US20;UPRR;US 20-95 IC

1.5 E. PARMA, Canyon, ID

Built 2017 Load: 44.7 t ADT: 3,900

SH 28

Good

Over: LEMHI RIVER

1.4 S. TENDOY, Lemhi, ID

Built 2019 Load: 45.0 t ADT: 820

STC 8223;KARCHER R

Good

Over: I 84;KARCHER ROAD GS

IN NAMPA;KARCHER ROAD, Canyon, ID

Built 2019 Load: 45.0 t ADT: 11,000

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

Showing 4,001-4,050 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.