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 95

Good

Over: UPRR;S. EASTPORT OP

1.1 S. EASTPORT, Boundary, ID

Built 2007 Load: 37.2 t ADT: 1,100

SH 97

Good

Over: BEAUTY CREEK

25.2 N. HARRISON, Kootenai, ID

Built 2009 Load: 37.2 t ADT: 3,100

PARMENTER LANE

Good

Over: CARMEN CREEK

1.5 N 2.8 E CARMEN, Lemhi, ID

Built 2011 Load: 37.2 t ADT: 80

US 95 NBL

Good

Over: UPRR;BITTER ROAD

6.0 N. WORLEY, Kootenai, ID

Built 2007 Load: 37.2 t ADT: 3,050

US 95 SBL

Good

Over: UPRR;BITTER ROAD

6.0 N. WORLEY, Kootenai, ID

Built 2007 Load: 37.2 t ADT: 3,050

SH 55

Good

Over: PAYETTE RIVER

HORSESHOE BEND SCL, Boise, ID

Built 2021 Load: 37.3 t ADT: 8,400

I 90B LOOP

Good

Over: S.FK.COEUR DALENE RIVER

IN MULLAN, Shoshone, ID

Built 2014 Load: 37.3 t ADT: 450

US 95

Good

Over: RACE CREEK

0.7 N. RIGGINS, Idaho, ID

Built 2015 Load: 37.3 t ADT: 2,200

SH 97

Good

Over: I90 EB-WB; WOLF LODGE IC

9.1 E. COEUR DALENE, Kootenai, ID

Built 2016 Load: 37.3 t ADT: 3,100

LAKE HAZEL RD

Good

Over: NEW YORK CANAL

S BOISE, Ada, ID

Built 2018 Load: 37.3 t ADT: 6,500

S3837;STRK DAM CTF

Good

Over: MIDDLE LINE CANAL

AT STRIKE DAM, Elmore, ID

Built 1959 Load: 37.3 t ADT: 330

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

HOOPER LANE

Good

Over: BIG SPRINGS

2.8 S 0.8 E MAY, Lemhi, ID

Built 2011 Load: 37.3 t ADT: 70

FS ROUTE NO. 209

Good

Over: LAVERNE CREEK

LAVERNE CREEK, Kootenai, ID

Built 1997 Load: 37.3 t ADT: 40

STC 5804;LIONS DEN

Good

Over: SNOW CREEK

2.1S 4.5W. BONNERS FERRY, Boundary, ID

Built 2018 Load: 37.6 t ADT: 300

NHM7683;GOWEN RD

Good

Over: UNION PACIFIC RR

IN BOISE, Ada, ID

Built 2022 Load: 37.6 t ADT: 6,700

SMA 7773;10TH AVE

Good

Over: INDIAN CREEK

IN CALDWELL; 10TH AVE, Canyon, ID

Built 2020 Load: 37.6 t ADT: 15,000

STC 8433; 11TH AVE

Good

Over: I 84;11TH AVE N. GS

IN NAMPA;11th AVE N., Canyon, ID

Built 2010 Load: 37.6 t ADT: 4,000

200 WEST ROAD

Good

Over: B-2 CANAL

1.5 N. 2.0 W. RUPERT, Minidoka, ID

Built 2020 Load: 37.6 t ADT: 200

E 1300 N

Good

Over: MARYSVILLE CANAL

3.4 E MARYSVILLE, Fremont, ID

Built 2013 Load: 37.6 t ADT: 200

STP3764;AMITY RD

Good

Over: RAWSON CANAL

3.5 S 1.8 W MERIDIAN, Ada, ID

Built 2016 Load: 37.6 t ADT: 4,100

FS ROUTE N0. 1312

Good

Over: MOORES CREEK

MOORES CREEK, Bonner, ID

Built 1980 Load: 37.6 t ADT: 40

LITTLE WEISER

Good

Over: LITTLE WEISER RIVER

LITTLE WEISER BRIDGE, Adams, ID

Built 2004 Load: 37.6 t ADT: 30

E 2100 S

Good

Over: I 84 EB-WB;E 2100 S GS

3.1 E. BLISS, Gooding, ID

Built 1977 Load: 37.8 t ADT: 60

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

I 86 WBL

Good

Over: UPRR;CHUBBUCK OVERPASS

0.4 E. CHUBBUCK, Bannock, ID

Built 2023 Load: 37.9 t ADT: 12,750

US 89

Good

Over: ST CHARLES CREEK

IN ST CHARLES, Bear Lake, ID

Built 2013 Load: 37.9 t ADT: 1,800

STC 1760; MAIN ST

Good

Over: RAPID CREEK

MAIN STREET, Bannock, ID

Built 2015 Load: 37.9 t ADT: 1,300

MULDOON CANYON RD

Good

Over: MULDOON CREEK

21 NE of Carey, Blaine, ID

Built 2021 Load: 37.9 t ADT: 80

STC2802;SOLDIER CR

Good

Over: SOLDIER CREEK

7.6 N. 1.6 W. SOLDIER, Camas, ID

Built 2020 Load: 37.9 t ADT: 100

1350 EAST ROAD

Good

Over: STRATTON CANAL

2.0 N 1.0 E RICHFIELD, Lincoln, ID

Built 2013 Load: 37.9 t ADT: 112

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

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

NO DATA ENTERED

Good

Over: CAYUSE CREEK

NO DATA ENTERED, Idaho, ID

Built 2017 Load: 37.9 t ADT: 15

FS ROUTE 6310

Good

Over: INDEPENDENCE CREEK

4 MI FROM TRAIL CREEK RS., Shoshone, ID

Built 1984 Load: 37.9 t ADT: 40

FDR 581

Good

Over: CAYUSE CREEK

14 MILES FROM POWELL R S, Clearwater, ID

Built 1962 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

MANN CK RD 50009

Good

Over: MANN CREEK

NO DATA ENTERED, Washington, ID

Built 1974 Load: 37.9 t ADT: 30

SH 11

Good

Over: QUARTZ CREEK;HOLLYWOOD

5.4 N. PIERCE, Clearwater, ID

Built 1975 Load: 38.1 t ADT: 200

I 15 SBL

Good

Over: DANSKIN CANAL

2.1 N. BLACKFOOT, Bingham, ID

Built 1962 Load: 38.1 t ADT: 12,750

US 20 WBL

Good

Over: STC 6708; ST LEON RD IC

4.0 S.W. UCON, Bonneville, ID

Built 2005 Load: 38.1 t ADT: 12,500

SH 33

Good

Over: CANYON CREEK

8.8 E. NEWDALE, Madison, ID

Built 2006 Load: 38.1 t ADT: 3,400

STC8223;NORTHSIDE

Good

Over: INDIAN CREEK

IN NAMPA, Canyon, ID

Built 1968 Load: 38.1 t ADT: 30,000

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

SH 75

Good

Over: SALMON RIVER; W. CLAYTON

2 W. CLAYTON, Custer, ID

Built 2008 Load: 38.1 t ADT: 660

STC2735;2900 EAST

Good

Over: LOW LINE CANAL

2S.TWIN FALLS;3575N2900E, Twin Falls, ID

Built 2010 Load: 38.1 t ADT: 1,400

STC2822;GLENDALE R

Good

Over: BIG WOOD RIVER

2.7 S. BELLEVUE, Blaine, ID

Built 1998 Load: 38.1 t ADT: 1,900

STC 3840;SWEET-OLA

Good

Over: SQUAW CREEK;N.SWEET BR.

2.1 N. SWEET, Gem, ID

Built 1982 Load: 38.1 t ADT: 450

Showing 3,701-3,750 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.