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

GARWOOD RD

Good

Over: US 95; UPRR; OLD US 95

AT GARWOOD, Kootenai, ID

Built 2022 Load: 35.0 t ADT: 2,900

NFSR 347

Good

Over: GRAYBACK GULCH

2.5 MI SW OF IDAHO CITY, Boise, ID

Built 2018 Load: 35.0 t ADT: 50

WHITEHAWK L.O. RD.

Good

Over: BEAR VALLEY CREEK

5 MI E. DEADWOOD RSRVOIR, Valley, ID

Built 1969 Load: 35.0 t ADT: 12

NO DATA ENTERED

Good

Over: HAZARD CREEK

NO DATA ENTERED, Idaho, ID

Built 1965 Load: 35.0 t ADT: 50

ROAD

Good

Over: TWIN CREEK

WEST OF TWIN CR. C.G., Lemhi, ID

Built 2007 Load: 35.0 t ADT: 10

60036

Good

Over: INDIAN CREEK

NO DATA ENTERED, Lemhi, ID

Built 2008 Load: 35.0 t ADT: 5

STC 1775;TURNER RD

Good

Over: PACIFICORP PENSTOCK

0.1 W GRACE, Caribou, ID

Built 2016 Load: 35.3 t ADT: 510

DOWTON LANE

Good

Over: PAHSIMEROI RIVER

5.0 S 3.4 E ELLIS, Custer, ID

Built 2016 Load: 35.3 t ADT: 100

N 2000 E

Good

Over: CONSOLIDATED FARMERS CNL

3.2 S. 3.7 W. ST ANTHONY, Fremont, ID

Built 2018 Load: 35.3 t ADT: 120

US 95

Good

Over: ROCK CREEK

6.3 N. 1.0 E. WINCHESTER, Nez Perce, ID

Built 2022 Load: 35.3 t ADT: 3,800

HOOPER LANE

Good

Over: LITTLE SPRINGS

3.0 S 0.8 E MAY, Lemhi, ID

Built 2011 Load: 35.3 t ADT: 70

AGENCY CREEK ROAD

Good

Over: AGENCY CREEK (BRIDGE 1)

0.5 E 0.5 S TENDOY, Lemhi, ID

Built 2016 Load: 35.3 t ADT: 30

FS ROUTE NO. 208

Good

Over: CDA RIVER

21 MI. FROM BABINS JCT., Shoshone, ID

Built 1965 Load: 35.3 t ADT: 40

SH 9

Good

Over: BIG BEAR CREEK

3.2 NW. DEARY, Latah, ID

Built 1982 Load: 35.4 t ADT: 920

I 15 SBL

Good

Over: GREAT WESTERN CANAL

15.9 N. BLACKFOOT, Bingham, ID

Built 1962 Load: 35.4 t ADT: 12,750

US 20 EBL

Good

Over: MENAN-LORENZO RD IC

4.2 N. RIGBY, Jefferson, ID

Built 2011 Load: 35.4 t ADT: 9,500

US 20 WBL

Good

Over: MENAN-LORENZO RD IC

4.2 N. RIGBY, Jefferson, ID

Built 2011 Load: 35.4 t ADT: 9,500

SH 55

Good

Over: UPRR

IN NAMPA, Canyon, ID

Built 2006 Load: 35.4 t ADT: 47,500

US 89

Good

Over: MONTPELIER CK;UPPER NRWS

4.3 E MONTPELIER, Bear Lake, ID

Built 2008 Load: 35.4 t ADT: 1,300

STC 1718;ARBON VLY

Good

Over: BANNOCK CR.;RATTLESNAKE

10.4 N. PAULINE, Power, ID

Built 1964 Load: 35.4 t ADT: 150

STC 1829; W 200 N

Good

Over: PEOPLES CANAL

0.3 N. 1.3 W. MORELAND, Bingham, ID

Built 1989 Load: 35.4 t ADT: 970

S 400 W

Good

Over: G CANAL

4.0 W 0.7 S BURLEY, Cassia, ID

Built 1994 Load: 35.4 t ADT: 990

FREEGOLD ROAD

Good

Over: SOLDIER CREEK

8.1 N 1.0 W. FAIRFIELD, Camas, ID

Built 2018 Load: 35.4 t ADT: 10

500 WEST ROAD

Good

Over: C CANAL

0.7 N. 1.0 E. PAUL, Minidoka, ID

Built 2001 Load: 35.4 t ADT: 100

SABIN ROAD

Good

Over: FARMERS COOP SEBREE CNL

2.7 E. PARMA, Canyon, ID

Built 1985 Load: 35.4 t ADT: 90

PHINNEY STREET

Good

Over: LAPWAI CREEK

IN CULDESAC ECL, Nez Perce, ID

Built 1966 Load: 35.4 t ADT: 90

US 95 SBL

Good

Over: FIGHTING CREEK

12.7 N. WORLEY, Kootenai, ID

Built 2007 Load: 35.4 t ADT: 3,350

RIDGE ROAD

Good

Over: W.FK.WEISER RIVER

6.2 N. 1.1 W. COUNCIL, Adams, ID

Built 2022 Load: 35.6 t ADT: 70

FUREY LANE

Good

Over: PAHSIMEROI RIVER

5.0 W PATTERSON, Lemhi, ID

Built 2015 Load: 35.6 t ADT: 90

Adams Boulevard

Good

Over: Adams Drainage

9.3S. 13.5 E. Arco, Butte, ID

Built 1993 Load: 35.6 t ADT: 491

3309: MARKET LAKE

Good

Over: Market Lake Canel

.2 mi SW of Twin Butte Rd, Madison, ID

Built 2000 Load: 35.6 t ADT: 25

NO DATA ENTERED

Good

Over: DEEP CR

NO DATA ENTERED, Idaho, ID

Built 2018 Load: 35.6 t ADT: 5

SILVER CREEK ROAD

Good

Over: SILVER CREEK

7 MI W DEADWOOD RSRVOIR, Valley, ID

Built 1967 Load: 35.6 t ADT: 60

Forest Road 277

Good

Over: South Fork of the Snake

PALISADES DAM, Bonneville, ID

Built 2012 Load: 36.0 t ADT: 100

STC 5783;EAST RVR

Good

Over: BIG CREEK

12.0 N. OF PRIEST RIVER, Bonner, ID

Built 2018 Load: 36.0 t ADT: 260

1420 NORTH ROAD

Good

Over: EAST MAIN CANAL

6.5 N 2.5 W RICHFIELD, Lincoln, ID

Built 2013 Load: 36.0 t ADT: 210

SMA 7029;EAGLE RD

Good

Over: DRY CREEK

1.0 N EAGLE, Ada, ID

Built 2018 Load: 36.0 t ADT: 5,000

S. CEMETERY ROAD

Good

Over: WILLOW CREEK

0.6 W. 0.2 S. MIDDLETON, Canyon, ID

Built 2021 Load: 36.0 t ADT: 25

N 1800 E

Good

Over: ST. ANTHONY CANAL

2.0 W. PARKER, Fremont, ID

Built 1975 Load: 36.0 t ADT: 240

FS ROUTE NO. 280

Good

Over: NF GROUSE CREEK

NF GROUSE, Bonner, ID

Built 2011 Load: 36.0 t ADT: 40

SH 3

Good

Over: EVANS CREEK

9.1 S. ROSE LAKE, Kootenai, ID

Built 1994 Load: 36.3 t ADT: 1,900

SH 4

Good

Over: CANYON CREEK

0.5 S. BURKE, Shoshone, ID

Built 1976 Load: 36.3 t ADT: 190

I 86 EBL

Good

Over: I 84 WBL

13.8 E BURLEY, Cassia, ID

Built 2020 Load: 36.3 t ADT: 18,000

I 15 NBL

Good

Over: LAVA SIDE CANAL

6.9 N. BLACKFOOT, Bingham, ID

Built 1962 Load: 36.3 t ADT: 12,750

I 15 SBL

Good

Over: LAVA SIDE CANAL

6.9 N. BLACKFOOT, Bingham, ID

Built 1962 Load: 36.3 t ADT: 12,750

US 20 WBL

Good

Over: STC 6706; HITT RD IC

2.0 S.W. UCON, Bonneville, ID

Built 2005 Load: 36.3 t ADT: 17,250

US 30

Good

Over: CEDAR CREEK DRAW

1.1 W. FILER, Twin Falls, ID

Built 2002 Load: 36.3 t ADT: 5,800

SH 33

Good

Over: TRAIL CREEK

1.5 E. VICTOR, Teton, ID

Built 2010 Load: 36.3 t ADT: 7,200

I 84 WBL

Good

Over: NEW YORK CANAL

IN BOISE;NEAR ORCHARD ST., Ada, ID

Built 1968 Load: 36.3 t ADT: 44,500

I 90 EBL & WBL

Good

Over: STC7405; PENN AVE GS

COEUR D ALENE ECL, Kootenai, ID

Built 2020 Load: 36.3 t ADT: 25,000

Showing 3,601-3,650 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.