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

N. GRAND LAKE WAY

Good

Over: FIVE MILE CREEK

3.45 N. MERIDIAN, Ada, ID

Built 2022 Load: 64.2 t ADT: 50

5TH SOUTH STREET

Good

Over: BEAVER CREEK

IN DUBOIS, Clark, ID

Built 2013 Load: 64.2 t ADT: 400

OLD HWY 46;500 E

Good

Over: CAMAS CREEK

3.1 S. 5.0 E. FAIRFIELD, Camas, ID

Built 2016 Load: 64.4 t ADT: 20

SMA7017;FL.FEATHER

Good

Over: DRY CREEK

0.8 N. 0.2 W. EAGLE, Ada, ID

Built 1991 Load: 64.4 t ADT: 8,000

MEDALLION ROAD

Good

Over: FIVE MILE CREEK

IN BOISE, Ada, ID

Built 1999 Load: 64.4 t ADT: 200

4TH AVE

Good

Over: LITTLE CANYON CREEK

IN GLENNS FERRY, Elmore, ID

Built 2018 Load: 64.8 t ADT: 20

REYNOLDS CR RD

Good

Over: REYNOLDS CREEK

0.5 S 10.2 W MURPHY, Owyhee, ID

Built 2012 Load: 65.1 t ADT: 200

SH 14

Good

Over: S.FK.CLEARWATER

8.7 S. JCT SH 13-14, Idaho, ID

Built 1985 Load: 65.3 t ADT: 150

SH 21

Good

Over: ELK CREEK

2.0 S. IDAHO CITY, Boise, ID

Built 2000 Load: 65.3 t ADT: 2,000

SMA9243;VICTORY RD

Good

Over: FIVE MILE CREEK

IN BOISE;VICTORY ROAD, Ada, ID

Built 1992 Load: 65.3 t ADT: 21,500

STC3725;LAKE SHORE

Good

Over: DEER FLAT HIGH LINE CNL

0.1 N 5.0 E MARSING, Canyon, ID

Built 2017 Load: 65.3 t ADT: 1,700

HAYLAND ROAD

Good

Over: MIDDLE LINE CANAL

2.1 N 1.0 E GRANDVIEW, Elmore, ID

Built 2004 Load: 65.3 t ADT: 200

BISON DRIVE

Good

Over: SAND CREEK

IN BOISE, Ada, ID

Built 2000 Load: 65.3 t ADT: 720

CAVANAUGH BAY ROAD

Good

Over: SOLDIER CREEK

22.6 N. PRIEST RIVER, Bonner, ID

Built 2017 Load: 67.1 t ADT: 1,800

LEESBURG ROAD

Good

Over: ARNETT CREEK

NO DATA ENTERED, Lemhi, ID

Built 1994 Load: 67.1 t ADT: 50

SH 29

Good

Over: EIGHTEEN MILE CREEK

0.24 EAST OF LEADORE, Lemhi, ID

Built 2019 Load: 67.7 t ADT: 170

SMA8133;HWY 44 EXT

Good

Over: NOTUS CANAL

1.3 S 4.8 E Notus, Canyon, ID

Built 2018 Load: 67.7 t ADT: 1,900

STC3710;SUMMER CMP

Good

Over: SQUAW CREEK

6.75 SW MARSING, Owyhee, ID

Built 1988 Load: 68.0 t ADT: 100

SH 78

Good

Over: BENNETT CREEK

3.0 W. HAMMETT, Elmore, ID

Built 1998 Load: 68.9 t ADT: 460

I 184 EBL

Good

Over: I 84 WBL

4.3 W. BOISE, Ada, ID

Built 2001 Load: 68.9 t ADT: 67,000

STC3756;DEER FLAT

Good

Over: MORA CANAL

5.2 S. 3.7 W. NAMPA, Canyon, ID

Built 2006 Load: 68.9 t ADT: 260

UPPER DALE ROAD

Good

Over: HORNET CREEK

7.7 N 8.4 W COUNCIL, Adams, ID

Built 1999 Load: 69.9 t ADT: 20

RIM ROAD

Good

Over: DEER FLAT HIGH LINE

4.0 S 3.6 W NAMPA CITY CN, Canyon, ID

Built 2013 Load: 69.9 t ADT: 140

US 95

Good

Over: LAPWAI CREEK

2.6 N. 1.2 E. WINCHESTER, Lewis, ID

Built 2020 Load: 70.3 t ADT: 3,500

SH 6

Good

Over: E.FK.MEADOW CREEK

6.3 N. HARVARD, Latah, ID

Built 1991 Load: 70.8 t ADT: 710

OWYHEE STREET

Good

Over: RIDENBAUGH CANAL

IN BOISE, Ada, ID

Built 1992 Load: 70.8 t ADT: 1,600

STC6700;PIONEER RD

Good

Over: SIDEHILL CANAL

2.7 S. 2.2 W. IDAHO FALLS, Bonneville, ID

Built 1981 Load: 70.8 t ADT: 1,400

STATELINE RD;WY114

Good

Over: JACKKNIFE CREEK

1.5 Miles N. of ETNA, Bonneville, ID

Built 2002 Load: 70.8 t ADT: 115

I 15 SBL

Good

Over: CAMAS CREEK

4.6 N. HAMER, Jefferson, ID

Built 1989 Load: 71.7 t ADT: 1,700

SWALE ROAD

Good

Over: RENWYCK CREEK

3 MI N OF SAGEHEN RSRVOIR, Gem, ID

Built 2006 Load: 72.3 t ADT: 50

US 93

Good

Over: N. FORK SALMON RIVER

15.1 N. NORTH FORK, Lemhi, ID

Built 1997 Load: 73.5 t ADT: 730

STC8215;WEISER RVR

Good

Over: GALLOWAY CANAL

0.3 S. 4.9 E. WEISER, Washington, ID

Built 1993 Load: 74.4 t ADT: 320

ELK SUMMIT RD

Good

Over: PILOT CREEK

12.9 N 2.1 W YELLOW PINE, Valley, ID

Built 2003 Load: 75.3 t ADT: 15

STC2757;NORTH ROAD

Good

Over: J COULEE CANAL

1.8 N JEROME, Jerome, ID

Built 2014 Load: 75.5 t ADT: 2,800

STC 7073;S.COLE RD

Good

Over: NEW YORK CANAL

ON S.COLE RD;0.3N.VALLEJO, Ada, ID

Built 1989 Load: 76.2 t ADT: 2,200

1000 EAST ROAD

Good

Over: N.FK. LEIGH CREEK

0.2 N. 3.5 E. TETONIA, Teton, ID

Built 2004 Load: 76.2 t ADT: 150

CLEAR CREEK ROAD

Good

Over: SACK CREEK

24 N. LOWMAN, Valley, ID

Built 2010 Load: 76.2 t ADT: 30

N. ECHOHAWK WAY

Good

Over: FARMERS UNION CANAL

IN EAGLE, Ada, ID

Built 1999 Load: 78.0 t ADT: 200

STC5777;REEDER BAY

Good

Over: GRANITE CREEK

0.5 N. 3.1 E. NORDMAN, Bonner, ID

Built 1996 Load: 78.0 t ADT: 890

E 500 N

Good

Over: ENTERPRISE CANAL

2.9 S 0.2 W CHESTER, Fremont, ID

Built 2011 Load: 78.0 t ADT: 70

W 600 N

Good

Over: MAIN DRAIN

6.0 N Rupert, Minidoka, ID

Built 2023 Load: 78.1 t ADT: 10

SMA8683;BLACK CAT

Good

Over: RIDENBAUGH CANAL

1.3 S. 3.1 W. MERIDIAN, Ada, ID

Built 1992 Load: 78.9 t ADT: 4,500

US 20

Good

Over: SOLOMAN DRAIN

CALDWELL ECL, Canyon, ID

Built 2023 Load: 79.1 t ADT: 15,500

VANDERDASSON RD

Good

Over: SEVEN MILE SLOUGH

0.1 S. 4.4 W. EMMETT, Gem, ID

Built 2013 Load: 79.7 t ADT: 480

E 10TH STREET

Good

Over: LAST CHANCE CANAL

0.6 S 1.1 E EMMETT, Gem, ID

Built 2008 Load: 79.8 t

SH 3

Good

Over: CHILDS CREEK

5.2 N. CLARKIA, Shoshone, ID

Built 2002 Load: 80.7 t ADT: 440

STP 9463;FIVE MILE

Good

Over: RIDENBAUGH CANAL

0.5 S. 3.9 E. MERIDIAN, Ada, ID

Built 1995 Load: 80.7 t ADT: 23,500

US 89

Good

Over: MONTPELIER CREEK

7.0 E. MONTPELIER, Bear Lake, ID

Built 2003 Load: 81.6 t ADT: 1,300

SH 43

Good

Over: WILLOW CREEK

2.0 S. UCON, Bonneville, ID

Built 1994 Load: 83.5 t ADT: 6,100

STC2777;SHOESTRING

Good

Over: X-4 LATERAL CANAL

5.0 S. 1.5 W. GOODING, Gooding, ID

Built 1980 Load: 83.5 t ADT: 800

Showing 4,301-4,350 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.