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

STC 3740;NOTUS RD

Fair

Over: BOISE RIVER;NOTUS BRIDGE

0.2 S. NOTUS, Canyon, ID

Built 1996 Load: 36.3 t ADT: 2,800

PHILBIN ROAD

Fair

Over: I 86 EB-WB;PHILBIN RD GS

1.5 W. CHUBBUCK, Bannock, ID

Built 1968 Load: 36.3 t ADT: 6,900

PEGRAM ROAD

Fair

Over: BEAR RIVER;W.BORDER BR.

0.2 S. 0.4 W. BORDER WYO., Bear Lake, ID

Built 1978 Load: 36.3 t ADT: 30

STC 1821;BASELINE

Fair

Over: W BR SNAKE RVR VLY CANAL

1.0 S 0.1 W SHELLEY, Bingham, ID

Built 2001 Load: 36.3 t ADT: 2,000

SANDY ROAD

Fair

Over: NORTH CANAL

2.5 S. 1.2 W. BLACKFOOT, Bingham, ID

Built 1955 Load: 36.3 t ADT: 200

KIMBALL; N 400 E

Fair

Over: W BR SNAKE R VALLEY CNL

8.4 NE. BLACKFOOT, Bingham, ID

Built 1980 Load: 36.3 t ADT: 110

BUTTE ROUND ROAD

Fair

Over: DESERT DRAIN

6.3 W. 0.8 N SPRINGFIELD, Bingham, ID

Built 1979 Load: 36.3 t ADT: 150

COUNTY LINE ROAD

Fair

Over: I 15 NB-SB;CO.LINE RD.GS

19.1 N. BLACKFOOT, Bingham, ID

Built 1962 Load: 36.3 t ADT: 160

950 EAST ROAD

Fair

Over: MAIN SOUTHSIDE CANAL

0.9 N 1.0 E DECLO, Cassia, ID

Built 2008 Load: 36.3 t ADT: 200

1300 SOUTH ROAD

Fair

Over: MILNER GOODING CANAL

4.0 S. 4.8 E. HAZELTON, Jerome, ID

Built 1975 Load: 36.3 t ADT: 410

VINYARD ROAD

Fair

Over: I 84;VINYARD RD GS

6.2 E. TWIN FALLS, Jerome, ID

Built 1965 Load: 36.3 t ADT: 70

200 WEST ROAD

Fair

Over: I 84;200 WEST RD GS

1.0 N. 3.0 E. HEYBURN, Minidoka, ID

Built 1990 Load: 36.3 t ADT: 150

4300 NORTH RD

Fair

Over: CEDAR DRAW

4.0N 1.9W FILER;JRDN COR, Twin Falls, ID

Built 1968 Load: 36.3 t ADT: 380

MURPHY ROAD

Fair

Over: WALDVOGEL CANAL

2.5 S. 3.0 W. KUNA, Ada, ID

Built 1971 Load: 36.3 t ADT: 50

WOODLAND ROAD

Fair

Over: GOOSE CREEK

0.2 S. 1.2 E. MEADOWS, Adams, ID

Built 1997 Load: 36.3 t ADT: 80

JACKSON CREEK RD

Fair

Over: COTTONWOOD CREEK

2.4 S. 1.0 W. COUNCIL, Adams, ID

Built 1955 Load: 36.3 t ADT: 50

SLIDE GULCH ROAD

Fair

Over: SMITH CREEK

0.1 N. 2.7 W. PRAIRIE, Elmore, ID

Built 1966 Load: 36.3 t ADT: 120

JACKSON ROAD

Fair

Over: MANN CREEK

7.4 N. 4.8 E. WEISER, Washington, ID

Built 1973 Load: 36.3 t ADT: 90

B AVE

Fair

Over: S. FORK CLEARWATER

IN KOOSKIA;B AVE-FRONT ST, Idaho, ID

Built 1963 Load: 36.3 t ADT: 100

STC 4721;BRIDGE ST

Fair

Over: S.FK.CLEARWATER RIVER

IN STITES, Idaho, ID

Built 1961 Load: 36.3 t ADT: 760

HATTER CREEK ROAD

Fair

Over: HATTER CREEK

3.2 S. 0.5 E. PRINCETON, Latah, ID

Built 1982 Load: 36.3 t ADT: 30

E.FK.PINE CREEK RD

Fair

Over: DOUGLAS CREEK

4.8 S. 2.2 W. WARDNER, Shoshone, ID

Built 1978 Load: 36.3 t ADT: 30

STC3895;YELLOWPINE

Fair

Over: TROUT CREEK

14 S. YELLOW PINE, Valley, ID

Built 1985 Load: 36.3 t ADT: 70

FS ROUTE NO. 2545

Fair

Over: COW CREEK

COW CREEK, Boundary, ID

Built 1964 Load: 36.3 t ADT: 50

NO DATA ENTERED

Fair

Over: LICK CREEK

NO DATA ENTERED, Valley, ID

Built 1982 Load: 36.3 t ADT: 50

SH 5

Fair

Over: SMRR;UPRR;PLUMMER CRK

IN PLUMMER, Benewah, ID

Built 2016 Load: 36.6 t ADT: 3,400

BEAVER-N. FK

Fair

Over: CAVE CREEK

27 MI FROM PIERCE ID, Clearwater, ID

Built 1963 Load: 36.6 t ADT: 100

CAMP GRD. RD. 221B

Fair

Over: SLATE CREEK

ROCKY BLUFF C.G., Idaho, ID

Built 1957 Load: 36.6 t ADT: 50

FDR 373

Fair

Over: NF SPRUCE CREEK

BRUSHY FK, Idaho, ID

Built 2008 Load: 36.6 t ADT: 50

I 84 ON RAMP

Fair

Over: INDIAN CREEK

IN NAMPA, Canyon, ID

Built 2006 Load: 36.9 t ADT: 18,500

ASPEN DRIVE

Fair

Over: WARM SPRINGS CREEK

0.7 N. 1.7 W. KETCHUM, Blaine, ID

Built 1991 Load: 36.9 t ADT: 390

100 EAST ROAD

Fair

Over: B-2 CANAL

2.0 N. 1.0 E. Rupert, Minidoka, ID

Built 2017 Load: 36.9 t ADT: 100

HOT SPRINGS ROAD

Fair

Over: BRUNEAU RIVER

6.1 S. 3.8 E. BRUNEAU, Owyhee, ID

Built 1989 Load: 36.9 t ADT: 60

3175 NORTH

Fair

Over: BIG LOST RIVER

0.2 N. 0.4 E. MOORE, Butte, ID

Built 1935 Load: 36.9 t ADT: 200

FS ROUTE NO. 208

Fair

Over: CDA RIVER

19.8 MI. FROM BABINS JCT., Shoshone, ID

Built 1966 Load: 36.9 t ADT: 40

FS ROUTE NO. 278

Fair

Over: NORTH GOLD CREEK

NORTH GOLD, Bonner, ID

Built 1983 Load: 36.9 t ADT: 50

FS ROUTE NO. 636

Fair

Over: GRASS CREEK

GRASS CREEK, Boundary, ID

Built 1973 Load: 36.9 t ADT: 50

NO DATA ENTERED

Fair

Over: ELDORADO CREEK

FAN CREEK BRIDGE, Idaho, ID

Built 1974 Load: 36.9 t ADT: 20

FOREST ROAD 492

Fair

Over: TWENTY MILE CREEK

NO DATA ENTERED, Idaho, ID

Built 1958 Load: 36.9 t ADT: 40

I 86 WBL

Fair

Over: FARM RD;MACHINE PASS GS

20.3 E. BURLEY, Cassia, ID

Built 1960 Load: 37.2 t ADT: 3,850

I 86 WBL

Fair

Over: ROCK CR;MASSACRE ROCK BR

12.1 W. AMERICAN FALLS, Power, ID

Built 1963 Load: 37.2 t ADT: 3,850

I 15 SBL

Fair

Over: STC 1762;PORTNEUF RD IC

3.6 S. POCATELLO, Bannock, ID

Built 1963 Load: 37.2 t ADT: 9,500

I 15 NBL

Fair

Over: PRIVATE RD.;MACHINE PASS

6.9 N. POCATELLO, Bannock, ID

Built 1959 Load: 37.2 t ADT: 14,250

I 15 SBL

Fair

Over: PRIVATE RD.;MACHINE PASS

6.9 N. POCATELLO, Bannock, ID

Built 1959 Load: 37.2 t ADT: 13,000

I 15 NBL

Fair

Over: SPENCER ROAD IC

IN SPENCER, Clark, ID

Built 1969 Load: 37.2 t ADT: 1,850

I 15 SBL

Fair

Over: SPENCER ROAD IC

IN SPENCER, Clark, ID

Built 1969 Load: 37.2 t ADT: 1,850

I 15 NBL

Fair

Over: CO.RD.;STODDARD CREEK IC

4.0 N. SPENCER, Clark, ID

Built 1969 Load: 37.2 t ADT: 1,750

I 15 SBL

Fair

Over: CO.RD.;STODDARD CREEK IC

4.0 N. SPENCER, Clark, ID

Built 1969 Load: 37.2 t ADT: 1,750

I 15

Fair

Over: FRONTAGE ROAD GS

6.8 N. SPENCER, Clark, ID

Built 1969 Load: 37.2 t ADT: 3,500

NHS 6710;YORK RD

Fair

Over: SNAKE RIVER

2.9 S. IDAHO FALLS SCL, Bonneville, ID

Built 1963 Load: 37.2 t ADT: 6,300

Showing 2,251-2,300 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.