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 44

Fair

Over: MIDDLETON CANAL

1.8 W. EAGLE, Ada, ID

Built 1959 Load: 24.5 t ADT: 9,700

I 84 EBL

Fair

Over: SOUTHSIDE CANAL

9.4 E. BURLEY, Cassia, ID

Built 1960 Load: 24.5 t ADT: 9,000

I 84 WBL

Fair

Over: SOUTHSIDE CANAL

9.4 E. BURLEY, Cassia, ID

Built 1960 Load: 24.5 t ADT: 9,000

I 84 WBL

Fair

Over: RAFT RIVER

10.1 N. SUBLETT, Cassia, ID

Built 1967 Load: 24.5 t ADT: 5,750

SH 75

Fair

Over: FRENCHMAN CREEK

1.2 SE SAWTOOTH CITY, Blaine, ID

Built 1974 Load: 24.5 t ADT: 970

STC2715;4100 N. RD

Fair

Over: CEDAR DRAW

2.0 N. 0.8 W. FILER, Twin Falls, ID

Built 1932 Load: 24.5 t ADT: 2,600

REID SPRING ROAD

Fair

Over: RAFT RIVER

3.5 S. 1.0 E. ALMO, Cassia, ID

Built 2001 Load: 24.5 t ADT: 200

STC6724; W 65TH S

Fair

Over: SIDEHILL CANAL

0.6 S. 5.4 W. IDAHO FALLS, Bonneville, ID

Built 1957 Load: 24.5 t ADT: 110

ASHTON-FLAGG RANCH

Fair

Over: FARMERS OWN CANAL

9.3 N. DRUMMOND, Fremont, ID

Built 1969 Load: 24.5 t ADT: 470

STP8393;FRANKLIN B

Fair

Over: PHYLLIS CANAL

IN NAMPA;FRANKLIN BLVD., Canyon, ID

Built 1963 Load: 24.5 t ADT: 23,000

STP8393;FRANKLIN B

Fair

Over: PHYLLIS CANAL

IN NAMPA;FRANKLIN BLVD., Canyon, ID

Built 1963 Load: 24.5 t ADT: 23,000

100 WEST ST

Fair

Over: ST. CHARLES CR N. BRIDGE

IN CITY OF ST. CHARLES, Bear Lake, ID

Built 1920 Load: 24.5 t ADT: 50

S. LAVASIDE ROAD

Fair

Over: PEOPLES CANAL

0.5 N. 1.8 W. KIMBALL, Bingham, ID

Built 1986 Load: 24.5 t ADT: 95

POLE CREEK ROAD

Fair

Over: SALMON RIVER

0.1S 0.2E SAWTOOTH CITY, Blaine, ID

Built 1974 Load: 24.5 t ADT: 50

OLD HWY 46;500 E

Fair

Over: CAMAS CREEK

3.4 S. 5.0 E. FAIRFIELD, Camas, ID

Built 1960 Load: 24.5 t ADT: 20

2200 EAST ROAD

Fair

Over: LITTLE WOOD RIVER

0.2 S. 3.0 E. GOODING, Gooding, ID

Built 1940 Load: 24.5 t ADT: 30

1010 SOUTH ROAD

Fair

Over: C CANAL

1.6 S. 2.8 E. HAZELTON, Jerome, ID

Built 1965 Load: 24.5 t ADT: 550

400 NORTH ROAD

Fair

Over: MAIN NORTHSIDE CANAL

0.6 N. 2.8 E. ACEQUIA, Minidoka, ID

Built 1998 Load: 24.5 t ADT: 300

3400 EAST ROAD

Fair

Over: LOW LINE CANAL

4.0 S. 1.0 W. KIMBERLY, Twin Falls, ID

Built 1982 Load: 24.5 t ADT: 90

GRIMES CREEK ROAD

Fair

Over: GRIMES CREEK

0.9 N. 4.7 W. IDAHO CITY, Boise, ID

Built 1960 Load: 24.5 t ADT: 20

SMA3748;USTICK RD

Fair

Over: DEER FLAT CANAL

3.0 S. 1.1 E. WILDER, Canyon, ID

Built 1998 Load: 24.5 t ADT: 1,200

BEET DUMP ROAD

Fair

Over: GRAND VIEW IRRG.DIST.CNL

1.8 N. 3.0 W. GRAND VIEW, Owyhee, ID

Built 1930 Load: 24.5 t ADT: 65

WEISER RIVER ROAD

Fair

Over: CRANE CREEK

3.2 N. 9.3 E. WEISER, Washington, ID

Built 1982 Load: 24.5 t ADT: 20

LOWER FORD CRK RD

Fair

Over: JIM FORD CREEK

2.8 S. 2.3 E. OROFINO, Clearwater, ID

Built 1977 Load: 24.5 t ADT: 480

LUKES GULCH ROAD

Fair

Over: THREE MILE CREEK

2.8 S. 0.4 W. STITES, Idaho, ID

Built 1965 Load: 24.5 t ADT: 420

FORKS ROAD

Fair

Over: POTLATCH R;E.HELMER BR

0.1 S. 2.1 E. HELMER, Latah, ID

Built 1977 Load: 24.5 t ADT: 20

HATTER CREEK ROAD

Fair

Over: HATTER CREEK

4.1 S. 0.5 E. PRINCETON, Latah, ID

Built 1970 Load: 24.5 t ADT: 30

ROCK CREEK ROAD

Fair

Over: ROCK CREEK; SE POTLATCH

1.2 S. 0.6 E. POTLATCH, Latah, ID

Built 1975 Load: 24.5 t ADT: 330

CENTRAL GRADE ROAD

Fair

Over: HATWAI CREEK

2.2 N. 3.0 E. LEWISTON, Nez Perce, ID

Built 1968 Load: 24.5 t ADT: 650

STC 7785;BRIDGE ST

Fair

Over: SAND CREEK

IN SANDPOINT;BRIDGE ST, Bonner, ID

Built 1969 Load: 24.5 t ADT: 7,200

RAPID LIGHTNING RD

Fair

Over: RAPID LIGHTNING CREEK

3.3 S. 6.4 E. SAMUELS, Bonner, ID

Built 1970 Load: 24.5 t ADT: 270

WOODLAND DRIVE

Fair

Over: LITTLE SAND CREEK

3.2 N. 1.0 W. SANDPOINT, Bonner, ID

Built 1992 Load: 24.5 t ADT: 250

S MCAVOY ROAD

Fair

Over: COUGAR CREEK

0.9S. 2.5W. COEUR DALENE, Kootenai, ID

Built 1940 Load: 24.5 t ADT: 10

IDAHO ROAD

Fair

Over: I 90 EB-WB;IDAHO RD GS

IN POST FALLS, Kootenai, ID

Built 1977 Load: 24.5 t ADT: 3,700

KINGS PASS RD

Fair

Over: PRICHARD CREEK

0.1 S. 0.1 W. MURRAY, Shoshone, ID

Built 1979 Load: 24.5 t ADT: 60

E FORK ROAD

Fair

Over: WILDHORSE CREEK

19 N.E. SUN VALLEY, Custer, ID

Built 1970 Load: 24.5 t ADT: 25

ENTRANCE ROAD

Fair

Over: LAPWAI CREEK

1.4 miles southeast of Jc, Nez Perce, ID

Built 1988 Load: 24.5 t ADT: 225

FIVE MILE ROAD

Fair

Over: FIVE MILE CREEK

1 MI N.E. OF HELENDE C.G., Boise, ID

Built 1981 Load: 24.6 t ADT: 10

NO DATA ENTERED

Fair

Over: MOOSE CREEK

NO DATA ENTERED, Lemhi, ID

Built 1979 Load: 24.6 t ADT: 50

FDR

Fair

Over: NORTH FORK OF WOOD RIVER

4 MILES NORTH SNRA HQDS, Blaine, ID

Built 1955 Load: 24.6 t ADT: 50

WAGONTOWN ROAD

Fair

Over: TRINITY CREEK

1 MI SW FEAHTERVILLE ID, Elmore, ID

Built 1966 Load: 24.9 t ADT: 25

KANE CREEK ROAD

Fair

Over: KANE CREEK

NO DATA ENTERED, Custer, ID

Built 1966 Load: 24.9 t ADT: 40

FDR 60099

Fair

Over: COPPER CREEK

COBALT WORK CENTER, Lemhi, ID

Built 1971 Load: 24.9 t ADT: 5

NO DATA ENTERED

Fair

Over: INDIAN CREEK

NO DATA ENTERED, Lemhi, ID

Built 1963 Load: 24.9 t ADT: 200

FDR

Fair

Over: SMILEY CREEK

SAWTOOTH VALLEY SMILEY CR, Blaine, ID

Built 1979 Load: 24.9 t ADT: 25

ROAD

Fair

Over: HENRYS LAKE OUTLET

NO DATA ENTERED, Fremont, ID

Built 1991 Load: 24.9 t ADT: 50

BROADFORD ROAD

Fair

Over: BIG WOOD R;W.BELLEVUE BR

0.2 N. 0.3 W. BELLEVUE, Blaine, ID

Built 1974 Load: 25.2 t ADT: 1,700

S3784;LOCUST GROVE

Fair

Over: RAWSON CANAL

5.3 S. 0.8 E. MERIDIAN, Ada, ID

Built 1973 Load: 25.2 t ADT: 1,500

SMA3343;LOCUST LN

Fair

Over: INDIAN CREEK

2.9 N. 2.7 W. KUNA, Ada, ID

Built 1967 Load: 25.2 t ADT: 5,100

STC 3811;FH 61 RD.

Fair

Over: S.FK.BOISE RIVER

0.5S 0.4W FEATHERVILLE, Elmore, ID

Built 1968 Load: 25.2 t ADT: 580

Showing 1,051-1,100 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.