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

LINDEN ROAD

Good

Over: FIFTEEN MILE CREEK

4.8 N 0.3 E NAMPA, Canyon, ID

Built 2013 Load: 83.5 t ADT: 4,300

US 93

Good

Over: WARM SPRING CREEK

6.8 S. CHALLIS, Custer, ID

Built 2018 Load: 84.2 t ADT: 760

STP 7446;SUNNYSIDE

Good

Over: BUTTE ARM CANAL

IN IDA.FALLS;SUNNYSIDE RD, Bonneville, ID

Built 2003 Load: 84.4 t ADT: 25,500

LAKE SHORE

Good

Over: RIDENBAUGH CANAL

4.7S 0.4W NAMPA CITY CTR, Canyon, ID

Built 2005 Load: 84.4 t ADT: 500

SMA 7674;MTN VIEW

Good

Over: PARADISE CREEK

MTN VIEW @ WHITE AVE., Latah, ID

Built 1997 Load: 87.1 t ADT: 5,700

W PINE CREEK ROAD

Good

Over: WEST PINE CREEK

1.0 N 4.0 W CAMBRIDGE, Washington, ID

Built 2010 Load: 88.9 t ADT: 50

STC 2842;E EY ROAD

Good

Over: RAFT RIVER

2.4 S. 6.4 E. ALMO, Cassia, ID

Built 2014 Load: 89.1 t ADT: 50

STC3742;WAMSTAD RD

Good

Over: GOLDEN GATE CANAL

2.6 N. 2.0 W. WILDER, Canyon, ID

Built 1993 Load: 89.8 t ADT: 80

SMA3683;BLACK CAT

Good

Over: RIDENBAUGH CANAL

3.0 N. 1.7 W. KUNA, Ada, ID

Built 1988 Load: 90.7 t ADT: 1,100

I 15B ON RAMP

Good

Over: SIDEHILL CANAL

1.2 W. IDAHO FALLS, Bonneville, ID

Built 2007 Load: 91.6 t ADT: 4,300

SMA 9183;TEN MILE

Good

Over: TEN MILE DRAIN

2.0 W. MERIDIAN, Ada, ID

Built 1990 Load: 91.6 t ADT: 24,500

STC 4719;RED RIVER

Good

Over: AMERICAN RIVER

1.2 S. 1.4 W. ELK CITY, Idaho, ID

Built 2014 Load: 91.7 t ADT: 150

SMA 7243;PROTEST

Good

Over: RIDENBAUGH CANAL

IN BOISE;PROTEST AVENUE, Ada, ID

Built 1992 Load: 93.4 t ADT: 10,500

US 20B

Good

Over: FARMERS FRIEND CANAL

2.0 N. ST ANTHONY, Fremont, ID

Built 1993 Load: 97.1 t ADT: 1,400

N FAWNRIDGE WAY

Good

Over: FIVE MILE CREEK

2.3 N 3.5 W. MERIDIAN, Ada, ID

Built 2022 Load: 97.2 t ADT: 100

STC 7012;HILL ROAD

Good

Over: DRY CREEK CANAL

0.1N 1.2E EAGLE, Ada, ID

Built 2015 Load: 97.2 t ADT: 3,400

SH 55

Good

Over: LOW LINE CANAL

3.5 N. MARSING, Canyon, ID

Built 2007 Load: 98.0 t ADT: 7,600

I 15B OFF RAMP

Good

Over: SIDEHILL CANAL

1.0 W. IDAHO FALLS, Bonneville, ID

Built 2007 Load: 99.9 t ADT: 4,200

US 20

Good

Over: OAKLAND WASTE DITCH

4.8 W. IDAHO FALLS, Bonneville, ID

Built 1976 Load: 99.9 t ADT: 4,500

US 20

Good

Over: DRY CREEK

0.9 W. CAREY, Blaine, ID

Built 1991 Load: 99.9 t ADT: 1,900

US 89

Good

Over: MONTPELIER CK;LOWER NRWS

4.1 E. MONTPELIER, Bear Lake, ID

Built 2008 Load: 99.9 t ADT: 1,300

US 91

Good

Over: WEST CACHE CANAL

3.2 N. PRESTON, Franklin, ID

Built 1993 Load: 99.9 t ADT: 2,300

US 95

Good

Over: DRAIN

1.6 S. CRAIGMONT, Lewis, ID

Built 1991 Load: 99.9 t ADT: 3,300

STC2739;3800 E. RD

Good

Over: LOW LINE CANAL

2.7 S. HANSEN, Twin Falls, ID

Built 1995 Load: 99.9 t ADT: 990

SMA7013;CLOVERDALE

Good

Over: RIDENBAUGH CANAL

1.5S. 2.8E MERIDIAN, Ada, ID

Built 2005 Load: 99.9 t ADT: 13,000

STP 7563;OVERLAND

Good

Over: RIDENBAUGH CANAL

1.2 S. 1.7 W. MERIDIAN, Ada, ID

Built 2009 Load: 99.9 t ADT: 9,000

STC4782;GRANGEMONT

Good

Over: WHISKEY CREEK

4.2 N. 8.9 E. OROFINO, Clearwater, ID

Built 1962 Load: 99.9 t ADT: 540

SMA 7363;AMERICANA

Good

Over: SETTLERS CANAL

IN BOISE;AMERICANA BLVD, Ada, ID

Built 1993 Load: 99.9 t ADT: 12,000

I 15B;SUNNYSIDE RD

Good

Over: SIDEHILL CANAL

0.7 W. IDAHO FALLS, Bonneville, ID

Built 2007 Load: 99.9 t ADT: 14,000

SMA 7754;D ST

Good

Over: PARADISE CREEK

IN MOSCOW, Latah, ID

Built 1950 Load: 99.9 t ADT: 1,500

MERIDIAN ROAD

Good

Over: A CANAL

0.8N 4.5 E HEYBURN, Minidoka, ID

Built 2011 Load: 99.9 t ADT: 1,200

3400 NORTH ROAD

Good

Over: ROCK CREEK

4.7 S. 3.6 E. TWIN FALLS, Twin Falls, ID

Built 1965 Load: 99.9 t ADT: 760

ALAMOSA LANE

Good

Over: FARMERS UNION CANAL

IN BOISE;ALAMOSA & STATE, Ada, ID

Built 1996 Load: 99.9 t ADT: 500

E. BRANCHWOOD

Good

Over: SQUAW CREEK

IN BOISE, Ada, ID

Built 2001 Load: 99.9 t ADT: 400

KING HILL RD

Good

Over: LITTLE CANYON CREEK

6.5N. 0.8E. GLENNS FERRY, Elmore, ID

Built 1999 Load: 99.9 t ADT: 20

CUT OFF ROAD

Good

Over: HOG CREEK

3.0 S 9.2 E MIDVALE, Washington, ID

Built 2007 Load: 99.9 t ADT: 90

BED ROCK FLAT ROAD

Good

Over: HOG CREEK

0.5S 9.3E MIDVALE, Washington, ID

Built 2002 Load: 99.9 t ADT: 50

DOLLAR ROAD

Good

Over: TRAIL CREEK

IN SUN VALLEY, Blaine, ID

Built 1988 Load: 99.9 t ADT: 5,000

US 93

Good

Over: N. FORK SALMON RIVER

15.1 N. NORTH FORK, Lemhi, ID

Built 1997 Load: 99.9 t ADT: 730

US 93

Good

Over: N. FORK SALMON RIVER

16.0 N. NORTH FORK, Lemhi, ID

Built 1997 Load: 99.9 t ADT: 730

FS ROUTE NO. 2450

Poor

Over: BLUE JOE CREEK

BLUE JOE CREEK, Boundary, ID

Built 1953 ADT: 50

FS ROUTE NO 2546

Poor

Over: BLUE JOE CREEK UPPER

BLUE JOE UPPER, Boundary, ID

Built 1953 ADT: 50

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

WILDERNESS ROAD

Poor

Over: DEEP CREEK;SHILO BRIDGE

1.2 S. NAPLES, Boundary, ID

Built 1960 Load: 2.7 t ADT: 30

COMMISSARY ROAD

Poor

Over: RAINEY CREEK

1.3 SE SWAN VALLEY, Bonneville, ID

Built 1985 Load: 2.7 t ADT: 75

Showing 4,351-4,400 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.