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

SMA 3686;JOPLIN RD

Fair

Over: HIGH LINE CANAL

2.5 S. 2.6 E. MIDDLETON, Canyon, ID

Built 1981 Load: 20.9 t ADT: 310

SMA8443;VICTORY RD

Fair

Over: RIDENBAUGH CANAL

4.0 E NAMPA, Canyon, ID

Built 1980 Load: 20.9 t ADT: 3,900

STC 3875;TEN DAVIS

Fair

Over: FARMERS COOP SEBREE CNL

2.3 N. 1.5 W. NOTUS, Canyon, ID

Built 1954 Load: 20.9 t ADT: 230

SMA3343;LOCUST LN

Fair

Over: NEW YORK CANAL

3.0S 4.3E NAMPA CITY CTR, Canyon, ID

Built 1973 Load: 20.9 t ADT: 5,100

EEL LANE

Fair

Over: LAWRENCE KENNEDY CANAL

0.7 S. 2.9 E. MIDDLETON, Canyon, ID

Built 1974 Load: 20.9 t ADT: 180

S3786;CHCKEN DINNR

Fair

Over: LOW LINE CANAL

4.5 N. 2.0 E. MARSING, Canyon, ID

Built 1965 Load: 20.9 t ADT: 560

DRY LAKE ROAD

Fair

Over: MORA CANAL

8.5 S. 2.1 W. NAMPA, Canyon, ID

Built 1987 Load: 20.9 t ADT: 70

STC 3799;USTICK RD

Fair

Over: PHYLLIS CANAL

3.8 N. 2.5 E. NAMPA, Ada, ID

Built 1965 Load: 20.9 t ADT: 3,900

STC 3869;CONWAY RD

Fair

Over: FARMERS COOP SEBREE CNL

1.0 N. 0.3 E. NOTUS, Canyon, ID

Built 1976 Load: 20.9 t ADT: 950

S. 9TH AVENUE

Fair

Over: INDIAN CREEK

IN CALDWELL;S.9TH AVE, Canyon, ID

Built 1968 Load: 20.9 t ADT: 750

17TH AVENUE NORTH

Fair

Over: INDIAN CREEK

NAMPA, Canyon, ID

Built 2001 Load: 20.9 t ADT: 800

STC 3809;MIDDLE FK

Fair

Over: BLACK WARRIOR CREEK

1.4 N. 8.1 W. ATLANTA, Elmore, ID

Built 1975 Load: 20.9 t ADT: 30

BOWMAN ROAD

Fair

Over: FARMERS COOP CANAL

1.0 S. 6.1 W. EMMETT, Gem, ID

Built 1967 Load: 20.9 t ADT: 330

STC 3833;DEWEY RD

Fair

Over: FARMERS COOP CANAL

1.0 S. 2.2 W. LETHA, Gem, ID

Built 1964 Load: 20.9 t ADT: 740

STC3831;LTL FRZOUT

Fair

Over: BLACK CANYON CANAL

1.9 S. 5.8 W. EMMETT, Gem, ID

Built 1973 Load: 20.9 t ADT: 1,900

RIVER RUN ROAD

Fair

Over: E.FK.JARBIDGE RIVER

0.2S 0.1E MURPHY HOT SPR, Owyhee, ID

Built 1922 Load: 20.9 t ADT: 25

PERSHALL RD

Fair

Over: B LINE CANAL

1.0 S. 0.4 W. MARSING, Owyhee, ID

Built 1960 Load: 20.9 t ADT: 150

BOULDER ROAD

Fair

Over: MEADOW CR;SPENCER RES BR

22.7 W. OREANA, Owyhee, ID

Built 1992 Load: 20.9 t ADT: 30

HOLLY ST.

Fair

Over: NOBLE CANAL

IN NEW PLYMOUTH;HOLLY ST, Payette, ID

Built 1972 Load: 20.9 t ADT: 200

ELGIN ROAD

Fair

Over: NOBLE CANAL

3.6S 4.4E NEW PLYMOUTH, Payette, ID

Built 1969 Load: 20.9 t ADT: 100

OASIS ROAD

Fair

Over: D LINE CANAL

11.5S 3.2E NEW PLYMOUTH, Payette, ID

Built 1975 Load: 20.9 t ADT: 680

STC3857;SND HOLLOW

Fair

Over: A LINE CANAL

5.6S 2.2E NEW PLYMOUTH, Payette, ID

Built 1965 Load: 20.9 t ADT: 1,300

GOLD DUST ROAD

Fair

Over: BIG CREEK

2.3 S. 3.0 E. CASCADE, Valley, ID

Built 1975 Load: 20.9 t ADT: 70

STC8217;COVE ROAD

Fair

Over: WEISER R;BACKWATER CH.BR

AT WEISER ECL;MAIN ST., Washington, ID

Built 1960 Load: 20.9 t ADT: 480

BRIDGE STREET

Fair

Over: PARADISE CREEK

IN MOSCOW;BRIDGE ST ECL, Latah, ID

Built 1972 Load: 20.9 t ADT: 150

RAPID LIGHTNING RD

Fair

Over: PACK RIVER

3.6 N. 4.8 E. KOOTENAI, Bonner, ID

Built 1974 Load: 20.9 t ADT: 270

CARIBOU CK;NF-2684

Fair

Over: CARIBOU CREEK

3.0 W. 3.0 N. SAMUELS, Bonner, ID

Built 1985 Load: 20.9 t ADT: 100

STC5802;HIGHLAND F

Fair

Over: DEEP CREEK;TED BRUHNS BR

0.7 N. 0.3 W. NAPLES, Boundary, ID

Built 1977 Load: 20.9 t ADT: 620

STC5907;DEEP CRK

Fair

Over: DEEP CREEK

1.0 N. 0.2 W. NAPLES, Boundary, ID

Built 1975 Load: 20.9 t ADT: 360

WOLF LODGE ROAD

Fair

Over: MARIE CREEK

0.7S. 8.2E. COEUR DALENE, Kootenai, ID

Built 1963 Load: 20.9 t ADT: 240

E. DUDLEY ROAD

Fair

Over: LATOUR CREEK;DUDLEY BR.

0.6 S. 1.7 W. CATALDO, Kootenai, ID

Built 1976 Load: 20.9 t ADT: 200

EMERALD CREEK RD

Fair

Over: ST MARIES RIVER

3.9 N. 3.3 W. CLARKIA, Shoshone, ID

Built 1978 Load: 20.9 t ADT: 180

ROSS GULCH

Fair

Over: W.FK.PINE CREEK

4.0 S. 0.9 W. PINEHURST, Shoshone, ID

Built 1975 Load: 20.9 t ADT: 150

W.FK.PINE CREEK RD

Fair

Over: W.FK.PINE CREEK

5.3 S. 1.5 W. PINEHURST, Shoshone, ID

Built 1975 Load: 20.9 t ADT: 100

CDA RIVER ROAD

Fair

Over: SHOSHONE CREEK

6.4 N. PRICHARD, Shoshone, ID

Built 1960 Load: 20.9 t ADT: 30

CDA RIVER ROAD

Fair

Over: LOST CREEK

4.9 N. PRICHARD, Shoshone, ID

Built 1953 Load: 20.9 t ADT: 30

SHELTON CEMETRY RD

Fair

Over: EAGLE ROCK CANAL

1.0 S. 1.0 W. RIRIE, Bonneville, ID

Built 1991 Load: 20.9 t ADT: 1,700

SOUTH 1ST EAST RD

Fair

Over: IDAHO CANAL

6.5 S. 0.5 E. IDAHO FALLS, Bonneville, ID

Built 1964 Load: 20.9 t ADT: 950

81ST NORTH ROAD

Fair

Over: IDAHO CANAL

5.3 N. 0.5 E. IDAHO FALLS, Bonneville, ID

Built 1966 Load: 20.9 t ADT: 480

HIGH BRIDGE ROAD

Fair

Over: WILLOW CREEK (WHITE BR)

11.0 S. 9.6 E. AMMON, Bonneville, ID

Built 1931 Load: 20.9 t ADT: 30

N 160 E; N 4950 E

Fair

Over: ANDERSON CANAL

0.1 S. 3.0 E. RIRIE, Bonneville, ID

Built 1964 Load: 20.9 t ADT: 550

W 17TH N

Fair

Over: OAKLAND CANAL

1.4 N. 3.2 W. IDAHO FALLS, Bonneville, ID

Built 1965 Load: 20.9 t ADT: 70

E. MILO ROAD

Fair

Over: ANDERSON CANAL

1.7 S. 4.5 W. RIRIE, Bonneville, ID

Built 1963 Load: 20.9 t ADT: 510

FAUST ROAD

Fair

Over: SIDEHILL CANAL

3.4 S. 5.2 W. IDAHO FALLS, Bonneville, ID

Built 1956 Load: 20.9 t ADT: 106

W 17TH N

Fair

Over: OAKLAND CANAL

1.4 N. 4.8 W. IDAHO FALLS, Bonneville, ID

Built 1973 Load: 20.9 t ADT: 70

PAYNE ROAD

Fair

Over: GREAT WESTERN CANAL

5.7 N. 1.0 W. IDAHO FALLS, Bonneville, ID

Built 1961 Load: 20.9 t ADT: 370

SMA6734;S 35TH W

Fair

Over: SIDEHILL CANAL

1.9 S. 3.2 W. IDAHO FALLS, Bonneville, ID

Built 1952 Load: 20.9 t ADT: 1,200

21ST ST.

Fair

Over: BUTTE ARM CANAL

IN IDAHO FALLS;21ST ST., Bonneville, ID

Built 1955 Load: 20.9 t ADT: 2,025

3350 WEST ROAD

Fair

Over: MOORE CANAL

1.4 N. MOORE, Butte, ID

Built 1979 Load: 20.9 t ADT: 200

SQUAW CREEK RD

Fair

Over: SALMON RIVER;SW.CLAYTON

0.7 S. 2.8 W. CLAYTON, Custer, ID

Built 1970 Load: 20.9 t ADT: 106

Showing 751-800 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.