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 3

Poor

Over: ST MARIES RIVER

3.3 N. CLARKIA, Shoshone, ID

Built 1955 Load: 29.9 t ADT: 440

US 91

Poor

Over: BLACKFOOT CANAL

1.0 N FIRTH, Bingham, ID

Built 1951 Load: 29.9 t ADT: 3,600

NORTH APPLE STREET

Poor

Over: LITTLE WOOD RIVER

IN SHOSHONE;N.APPLE ST, Lincoln, ID

Built 1920 Load: 29.9 t ADT: 200

STC 3809;MIDDLE FK

Poor

Over: QUEENS RIVER NO. 2

4.0 N. 4.0 W. ATLANTA, Elmore, ID

Built 1962 Load: 29.9 t ADT: 30

2416: TEAKETTLE RO

Poor

Over: Y-1 Canal

2.4 mi N of ID26, Gooding, ID

Built 1991 Load: 30.5 t ADT: 25

FS ROUTE NO. 427

Poor

Over: BOULDER CR CALLAHAN

BOULDER CREEK, Boundary, ID

Built 1961 Load: 30.5 t ADT: 50

FDR 103

Poor

Over: YOOSA CREEK

YOOSA CREEK BRIDGE, Idaho, ID

Built 1963 Load: 30.5 t ADT: 40

I 15 NBL

Poor

Over: I 15B;W.INKOM IC

0.5 W. INKOM, Bannock, ID

Built 1962 Load: 30.8 t ADT: 7,750

WILLIE RD

Poor

Over: I 15;WILLIE ROAD GS

4.5 S. BLACKFOOT, Bingham, ID

Built 1959 Load: 30.8 t ADT: 160

RUBY CREEK RD

Poor

Over: RUBY CREEK(#4)

3.3 N. 0.8 W. NAPLES, Boundary, ID

Built 1970 Load: 30.8 t ADT: 30

FDR 500

Poor

Over: ELDORADO CREEK

32 MILES FROM KAMIAH ID, Idaho, ID

Built 1967 Load: 31.1 t ADT: 99

CEMETARY RD

Poor

Over: BEAR CREEK

20.0 N. 11.6 W. COUNCIL, Adams, ID

Built 1983 Load: 31.8 t ADT: 5

RD 360

Poor

Over: SAVAGE CREEK

10 MI FROM POWELL RS, Idaho, ID

Built 2006 Load: 31.8 t ADT: 10

LONGHAUL ROAD

Poor

Over: COTTONWOOD CREEK

7.9 N. 0.5 W. GRANGEVILLE, Idaho, ID

Built 1960 Load: 32.4 t ADT: 30

N 4075 E

Poor

Over: MARYSVILLE CANAL

0.1 N. 3.7 E. MARYSVILLE, Fremont, ID

Built 1976 Load: 32.4 t ADT: 10

FS ROUTE NO. 1221

Poor

Over: GOLD CREEK

GOLD CREEK, Shoshone, ID

Built 1963 Load: 32.4 t ADT: 50

I 90B

Poor

Over: S.FK.CDA R;I-90B ARCH

IN WALLACE;BANK ST., Shoshone, ID

Built 1940 Load: 32.7 t ADT: 2,200

1150 EAST ROAD

Poor

Over: EAST MAIN CANAL

6.0 N. 1.0 W. RICHFIELD, Lincoln, ID

Built 1977 Load: 32.7 t ADT: 50

FS ROUTE NO. 1009

Poor

Over: GRASS CREEK

GRASS CR, Boundary, ID

Built 1972 Load: 32.7 t ADT: 50

BEAVER-LOON ROAD

Poor

Over: JORDAN CREEK

NO DATA ENTERED, Custer, ID

Built 1993 Load: 32.7 t ADT: 100

NO DATA ENTERED

Poor

Over: BOULDER CREEK

NO DATA ENTERED, Adams, ID

Built 1957 Load: 32.7 t ADT: 50

EAST FORK RD

Poor

Over: ROAD CREEK

5.8 S 5.6 E CLAYTON, Custer, ID

Built 2022 Load: 33.0 t ADT: 90

FDR 520

Poor

Over: YOOSA CREEK

27 MILES FROM PIERCE, Idaho, ID

Built 1963 Load: 34.0 t ADT: 40

FS ROUTE NO. 2361

Poor

Over: BEAVER CREEK

JCT W/SHOSHONE CO. RD.456, Shoshone, ID

Built 1983 Load: 34.3 t ADT: 50

I 15 NBL

Poor

Over: MAIN STREET GS

IN INKOM;MAIN ST., Bannock, ID

Built 1962 Load: 34.5 t ADT: 7,750

I 15 SBL

Poor

Over: MAIN STREET GS

IN INKOM;MAIN ST., Bannock, ID

Built 1962 Load: 34.5 t ADT: 7,750

LICK CREEK RD

Poor

Over: ZENA CREEK

9.0 N. 17.6 E. MCCALL, Valley, ID

Built 2021 Load: 34.7 t ADT: 40

NO DATA ENTERED

Poor

Over: BOULDER CREEK

NO DATA ENTERED, Lemhi, ID

Built 1966 Load: 35.3 t ADT: 200

SH 46

Poor

Over: MINEAR CREEK

28.9 N. GOODING, Camas, ID

Built 1955 Load: 36.3 t ADT: 590

I 90 EBL & WBL

Poor

Over: RR ROADBED/NO TRACKS

3.0 E. MULLAN, Shoshone, ID

Built 1972 Load: 36.3 t ADT: 8,300

WOODVILLE ROAD

Poor

Over: I 15 NB-SB;WOODVILLE GS

17.9 N. BLACKFOOT, Bingham, ID

Built 1962 Load: 36.3 t ADT: 130

FDR 382

Poor

Over: ELK CREEK

5 MILES FROM ELK RIVER ID, Clearwater, ID

Built 1961 Load: 36.3 t ADT: 20

FDR 382

Poor

Over: ELK CREEK

4 MILES FROM ELK RIVER ID, Clearwater, ID

Built 1961 Load: 36.3 t ADT: 20

AIRPORT ROAD

Poor

Over: I 86 EB-WB;AIRPORT IC

5.7 W. CHUBBUCK, Power, ID

Built 1968 Load: 37.2 t ADT: 1,300

SMA 7733;KIMBALL A

Poor

Over: INDIAN CREEK

IN CALDWELL;S.KIMBALL AVE, Canyon, ID

Built 1933 Load: 37.2 t ADT: 3,500

SALMON RIVER ROAD

Poor

Over: PINE CREEK

PINE CREEK, Lemhi, ID

Built 2012 Load: 37.3 t ADT: 350

NO DATA ENTERED

Poor

Over: OSIER CREEK

2.0 MI N OF OLD KELLY CR, Clearwater, ID

Built 1954 Load: 37.6 t ADT: 40

BIG FLAT ROAD

Poor

Over: BIG WILLOW CREEK

7.2N 16.6E NEW PLYMOUTH, Payette, ID

Built 1970 Load: 37.8 t ADT: 50

US 2

Poor

Over: PRIEST RIVER

AT PRIEST RIVER ECL, Bonner, ID

Built 1962 Load: 38.1 t ADT: 5,200

OR 86 (HWY 012)

Poor

Over: SNAKE RIVER (OXBOW)

ORE-IDAHO STATE LINE, Adams, ID

Built 1961 Load: 38.9 t ADT: 98

I 15 SBL

Poor

Over: I15B;UPRR;S.BLACKFOOT IC

3.8 S. BLACKFOOT, Bingham, ID

Built 1961 Load: 39.0 t ADT: 13,750

I 15 NBL

Poor

Over: I15B;UPRR;S.BLACKFOOT IC

3.8 S. BLACKFOOT, Bingham, ID

Built 1961 Load: 39.0 t ADT: 13,750

N 2700 E

Poor

Over: CROSSCUT CANAL

1.7 S. 3.2 E. ST ANTHONY, Fremont, ID

Built 1937 Load: 39.6 t ADT: 10

POTLATCH ROAD

Poor

Over: AGATHA CREEK TRESTLE

5.7 E. CALDER, Shoshone, ID

Built 1912 Load: 39.9 t ADT: 100

OLD CHILLI ROAD

Poor

Over: THOUSAND SPRINGS CREEK

12.6 N. 13.2 W. MACKAY, Custer, ID

Built 1926 Load: 39.9 t ADT: 80

1100 SOUTH ROAD

Poor

Over: C CANAL

3.0 S. 1.3 E. EDEN, Jerome, ID

Built 1975 Load: 40.5 t ADT: 200

BLUFF ROAD

Poor

Over: BIG WILLOW CREEK

2.1N 2.4E NEW PLYMOUTH, Payette, ID

Built 1962 Load: 40.5 t ADT: 130

CROOKED RIVER ROAD

Poor

Over: UPPER CROOKED RIVER

30.2 E 12.6 S GRANGEVILLE, Idaho, ID

Built 1965 Load: 40.8 t ADT: 50

NORTHSIDE RD

Poor

Over: BLACK PRINCE CREEK

0.5 S. 6.1 E. CALDER, Shoshone, ID

Built 1965 Load: 42.3 t ADT: 40

SH 162

Poor

Over: SEVEN MILE CREEK

2.9 S. KAMIAH, Idaho, ID

Built 1949 Load: 42.6 t ADT: 1,100

Showing 4,551-4,600 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.