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

I 84

Fair

Over: CO.RD.;HORSE BUTTE GS

16.6 E. BURLEY, Cassia, ID

Built 1963 Load: 32.7 t ADT: 12,000

MULLAN TRAIL RD

Fair

Over: I90;MULLAN TRAIL RD IC

1.0 E. COEUR DALENE, Kootenai, ID

Built 1991 Load: 32.7 t ADT: 950

US 93

Fair

Over: LATERAL NO. 1

25.1 N. NEVADA LINE, Twin Falls, ID

Built 2006 Load: 32.7 t ADT: 4,400

US 93

Fair

Over: R CANAL

13.2 N. TWIN FALLS, Jerome, ID

Built 1984 Load: 32.7 t ADT: 6,500

SH 75

Fair

Over: BELLEVUE CANAL

4.4 S. HAILEY, Blaine, ID

Built 1931 Load: 32.7 t ADT: 6,600

SH 75

Fair

Over: SMILEY CREEK

12.7 S. OBSIDIAN, Blaine, ID

Built 1977 Load: 32.7 t ADT: 750

US 95

Fair

Over: PAYETTE RIVER

1.8 S. PAYETTE SCL, Payette, ID

Built 1968 Load: 32.7 t ADT: 19,000

US 95

Fair

Over: SLATE CREEK

9.4 S. WHITEBIRD, Idaho, ID

Built 1969 Load: 32.7 t ADT: 2,200

US 95

Fair

Over: WHITEBIRD CREEK

AT WHITEBIRD WCL, Idaho, ID

Built 1975 Load: 32.7 t ADT: 2,700

US 95

Fair

Over: BLACKWELL SLOUGH

1.3 S. COEUR DALENE, Kootenai, ID

Built 1969 Load: 32.7 t ADT: 13,500

STC 1811;PEGRAM RD

Fair

Over: BEAR RIVER;PEGRAM BRIDGE

0.8 W. PEGRAM, Bear Lake, ID

Built 1970 Load: 32.7 t ADT: 100

STC2704;LILLY GR.

Fair

Over: SALMON FALLS CREEK

4.7 S. 0.1 E. CASTLEFORD, Twin Falls, ID

Built 1984 Load: 32.7 t ADT: 100

SMA7808;MIDDLETON

Fair

Over: MILL SLOUGH

MIDDLETON NE CITY LIMITS, Canyon, ID

Built 1999 Load: 32.7 t ADT: 3,400

STC 3811;PINE RD

Fair

Over: LIME CREEK

4.6 S. 1.8 E. PINE, Elmore, ID

Built 1984 Load: 32.7 t ADT: 580

MONTOUR ROAD

Fair

Over: PAYETTE RVR(MONTOUR BR)

0.6 N. 0.3 W. MONTOUR, Gem, ID

Built 1967 Load: 32.7 t ADT: 300

SMA 7505;N SPOKANE

Fair

Over: SPOKANE R.;POST FALLS BR

POST FALLS SCL, Kootenai, ID

Built 1971 Load: 32.7 t ADT: 6,200

STC 6705;E 113TH S

Fair

Over: IDAHO CANAL

1.0 N. 0.5 E. TAYLORVILLE, Bonneville, ID

Built 1977 Load: 32.7 t ADT: 780

STC 6715(N 3400 E)

Fair

Over: DRY BED CANAL

0.3 S. MENAN, Jefferson, ID

Built 1957 Load: 32.7 t ADT: 1,100

SMA7344;BRYDEN CYN

Fair

Over: SNAKE R;HIGH/SOUTHWAY BR

IN LEWISTON;BRYDEN EXT, Nez Perce, ID

Built 1982 Load: 32.7 t ADT: 21,000

STP 7363;AMERICANA

Fair

Over: BOISE RIVER

IN BOISE;AMERICANA BLVD, Ada, ID

Built 1994 Load: 32.7 t ADT: 12,000

KIMBALL RD;N 400 E

Fair

Over: W.BR.SNAKE R.VALLEY CNL

1.0 S. KIMBALL, Bingham, ID

Built 1979 Load: 32.7 t ADT: 110

LEMHI ROAD

Fair

Over: PEOPLES CANAL

1.5 N. 0.4 E. MORELAND, Bingham, ID

Built 1994 Load: 32.7 t ADT: 790

FOSTER CREEK RD

Fair

Over: CUB RIVER;FOSTER CRK BR.

7.3 E. PRESTON, Franklin, ID

Built 1998 Load: 32.7 t ADT: 20

SERENADE LANE

Fair

Over: TRAIL CREEK

0.6 S KETCHUM, Blaine, ID

Built 1995 Load: 32.7 t ADT: 500

950 EAST ROAD

Fair

Over: H CANAL

0.6S 1.0E DECLO;150S-950E, Cassia, ID

Built 2009 Load: 32.7 t ADT: 100

2400 EAST ROAD

Fair

Over: GOODING MAIN CANAL

0.7 S. 5.0 E. GOODING, Gooding, ID

Built 1933 Load: 32.7 t ADT: 20

E 2350 S

Fair

Over: I 84 EB-WB;TUTTLE IC

6.5 E. BLISS, Gooding, ID

Built 1977 Load: 32.7 t ADT: 860

EDEN ROAD

Fair

Over: I 84;EDEN RD GS

13.3 E. TWIN FALLS, Jerome, ID

Built 1966 Load: 32.7 t ADT: 200

820 NORTH ROAD

Fair

Over: DIETRICH CANAL

0.5 N. 0.4 E. RICHFIELD, Lincoln, ID

Built 1994 Load: 32.7 t ADT: 80

N. 3300 EAST RD.

Fair

Over: PERRINE COULEE

3.5 S. 3.3 E. TWIN FALLS, Twin Falls, ID

Built 1979 Load: 32.7 t ADT: 760

STC2768;5250 E. RD

Fair

Over: SNAKE RIVER;MILNER DAM

2.5 N. 7.5 E. MURTAUGH, Twin Falls, ID

Built 1986 Load: 32.7 t ADT: 340

E. CARMEL DRIVE

Fair

Over: FIVE MILE CREEK

IN MERIDIAN, Ada, ID

Built 1996 Load: 32.7 t ADT: 100

STC 7787;PLYMOUTH

Fair

Over: RIVERSIDE CANAL

IN CALDWELL;PLYMOUTH ST, Canyon, ID

Built 1930 Load: 32.7 t ADT: 2,000

STC3790;ALLENDALE

Fair

Over: LOW LINE CANAL

2.4 S. 2.0 E. WILDER, Canyon, ID

Built 1998 Load: 32.7 t ADT: 240

S3792;UPPR PLEASNT

Fair

Over: DEER FLAT CANAL

2.0 S. 2.5 E. WILDER, Canyon, ID

Built 1997 Load: 32.7 t ADT: 230

STC 3031;FARGO RD

Fair

Over: GOLDEN GATE CANAL

0.2 S. 1.0 W. WILDER, Canyon, ID

Built 1991 Load: 32.7 t ADT: 280

VAN SLYKE ROAD

Fair

Over: GOLDEN GATE CANAL

0.8 S. 3.0 E. WILDER, Canyon, ID

Built 1994 Load: 32.7 t ADT: 80

STC 3790;ALLENDALE

Fair

Over: GOLDEN GATE CANAL

0.6 S. 2.0 E. WILDER, Canyon, ID

Built 1992 Load: 32.7 t ADT: 240

LONKEY LANE

Fair

Over: LOWLINE CANAL

3.5 S. 5.5 E. WILDER, Canyon, ID

Built 1996 Load: 32.7 t ADT: 50

TUCKER ROAD

Fair

Over: LOW LINE CANAL

1.0 S. 4.0 E. WILDER, Canyon, ID

Built 1997 Load: 32.7 t ADT: 70

LOW PLEASANT RD

Fair

Over: GOLDEN GATE CANAL

1.0 S. 3.8 E. WILDER, Canyon, ID

Built 1994 Load: 32.7 t ADT: 80

STC 3851;HEXON RD

Fair

Over: MCCONNELL ISLAND DITCH

2.3 W. 0.2 S. PARMA, Canyon, ID

Built 1993 Load: 32.7 t ADT: 280

STC3798;PECKHAM RD

Fair

Over: GOLDEN GATE CANAL

1.1 W. WILDER, Canyon, ID

Built 1990 Load: 32.7 t ADT: 420

STC 3811;FH61 RD

Fair

Over: S.FK.BOISE RIVER

3.9 N. 1.1 E. PINE, Elmore, ID

Built 1963 Load: 32.7 t ADT: 580

OLD HWY 30

Fair

Over: ELMORE ST;ELMORE ST GS

IN GLENNS FERRY, Elmore, ID

Built 1955 Load: 32.7 t ADT: 940

GEM ISLND S ACCESS

Fair

Over: PAYETTE RIVER TRIBUTARY

IN EMMETT, Gem, ID

Built 2008 Load: 32.7 t ADT: 100

FIRST ST.SOUTH

Fair

Over: I 84;FIRST ST SOUTH GS

22.8 W. CALDWELL, Payette, ID

Built 1960 Load: 32.7 t ADT: 540

BLACK CANYON ROAD

Fair

Over: I 84;BLACK CANYON RD IC

13.1 W. CALDWELL, Payette, ID

Built 1960 Load: 32.7 t ADT: 1,600

E. HATTER CR. ROAD

Fair

Over: HATTER CREEK

3.6 S. 0.6 E. PRINCETON, Latah, ID

Built 1984 Load: 32.7 t ADT: 30

STC 4805;CEDAR RDG

Fair

Over: POTLATCH RIVER

1.6 N. 4.1 E. KENDRICK, Latah, ID

Built 1992 Load: 32.7 t ADT: 310

Showing 1,901-1,950 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.