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

NO DATA ENTERED

Good

Over: BLACKBIRD CREEK

NO DATA ENTERED, Lemhi, ID

Built 1973 Load: 32.7 t ADT: 50

ROAD

Good

Over: HYNDMAN CREEK

HINDMAN CREEK, Blaine, ID

Built 1994 Load: 32.7 t ADT: 80

SH 53

Good

Over: US 95

3.9 E. RATHDRUM, Kootenai, ID

Built 2020 Load: 33.0 t ADT: 3,400

S5750;WF PINE CRK

Good

Over: W.FK.PINE CREEK

3.6 S. PINEHURST, Shoshone, ID

Built 2013 Load: 33.0 t ADT: 620

RUBY CREEK ROAD

Good

Over: RUBY CREEK (#3)

3.3 N. 0.7 W. NAPLES, Boundary, ID

Built 2020 Load: 33.0 t ADT: 30

HOOPER LANE

Good

Over: BIG SPRINGS CONN. DITCH

2.9 S 0.8 E MAY, Lemhi, ID

Built 2011 Load: 33.0 t ADT: 70

NO DATA ENTERED

Good

Over: LITTLE NF CLEARWATER

NO DATA ENTERED, Shoshone, ID

Built 2014 Load: 33.0 t ADT: 40

R0AD

Good

Over: DEER CREEK

NO DATA ENTERED, Boundary, ID

Built 2015 Load: 33.0 t ADT: 40

NO DATA ENTERED

Good

Over: WAWAALAMNINE CREEK

JUNCTION RD 108 & 5613, Idaho, ID

Built 1978 Load: 33.0 t ADT: 30

PARK CK. C.G. RD.

Good

Over: CLEAR CREEK

3 MI N.E. OF LOWMAN ID, Boise, ID

Built 1957 Load: 33.0 t ADT: 25

SUNDERLAND DR.

Good

Over: SETTLERS CANAL

IN BOISE;SUNDERLAND DR., Ada, ID

Built 1972 Load: 33.3 t ADT: 991

SH 22

Good

Over: I 15 NB-SB; DUBOIS IC

IN DUBOIS, Clark, ID

Built 2012 Load: 33.4 t ADT: 1,700

I 84 EBL

Good

Over: PHYLLIS CANAL

IN NAMPA, Canyon, ID

Built 2012 Load: 33.4 t ADT: 52,750

I 84 EBL

Good

Over: KUNA RD; BLACKS CREEK RD

9.2 E. BOISE ECL, Ada, ID

Built 2020 Load: 33.4 t ADT: 14,500

E 400 N

Good

Over: CROSSCUT CANAL

4.0 N 0.7 W NEWDALE, Fremont, ID

Built 2013 Load: 33.4 t ADT: 250

700 EAST ROAD

Good

Over: DAUGHERTY CREEK

0.8 S. 7.0 E. FAIRFIELD, Camas, ID

Built 2022 Load: 33.4 t ADT: 30

COTTONWOOD ROAD

Good

Over: COTTONWOOD CREEK

3.3 S. 2.8 E. COUNCIL, Adams, ID

Built 2022 Load: 33.4 t ADT: 80

BIG CREEK ROAD

Good

Over: BIG CREEK

3.6 S. BIG CREEK, Valley, ID

Built 2014 Load: 33.4 t ADT: 10

STC6870;PAHSIMEROI

Good

Over: BIG CREEK FISH PASSAGE

9.0 S. 10.4 E. MAY, Custer, ID

Built 2014 Load: 33.4 t ADT: 30

FS ROUTE NO. 278

Good

Over: JOHNSON CREEK

JOHNSON CREEK, Bonner, ID

Built 2022 Load: 33.4 t ADT: 50

NO DATA ENTERED

Good

Over: NO DATA ENTERED

NO DATA ENTERED, Shoshone, ID

Built 2015 Load: 33.4 t ADT: 40

SH 9

Good

Over: E.FK.BEAR CREEK

2.3 NW. DEARY, Latah, ID

Built 1982 Load: 33.6 t ADT: 1,600

US 20

Good

Over: HENRYS FK. SNAKE RIVER

17.8 N. ASHTON, Fremont, ID

Built 2001 Load: 33.6 t ADT: 6,300

SH 48

Good

Over: FARMERS FRIEND CANAL

0.5 W. RIRIE, Jefferson, ID

Built 1983 Load: 33.6 t ADT: 1,900

SH 75

Good

Over: GINI CANAL

2.4 S. CHALLIS, Custer, ID

Built 1988 Load: 33.6 t ADT: 1,100

SH 200

Good

Over: MOSQUITO CREEK

CLARK FORK ECL, Bonner, ID

Built 2006 Load: 33.6 t ADT: 1,300

STC 3988;ROSEBERRY

Good

Over: BOULDER CREEK

AT DONNELLY ECL, Valley, ID

Built 1996 Load: 33.6 t ADT: 350

BARRON LN;600 WEST

Good

Over: CAMAS CREEK

3.2 S. 2.0 E. CORRAL, Camas, ID

Built 2003 Load: 33.6 t ADT: 30

BASELINE ROAD

Good

Over: WILLOW CREEK

2.1 N. 11.5 E. FAIRFIELD, Camas, ID

Built 1989 Load: 33.6 t ADT: 170

BASELINE ROAD

Good

Over: C-2 CANAL

1.0 N. 0.8 W. PAUL, Minidoka, ID

Built 1999 Load: 33.6 t ADT: 150

STC 3800;CARBARTON

Good

Over: N.FK.PAYETTE RIVER

6.8 S. 0.5 E. CASCADE, Valley, ID

Built 1977 Load: 33.6 t ADT: 320

STC 3006;MANN CRK

Good

Over: GALLOWAY CANAL

0.1 S. 5.4 E. WEISER, Washington, ID

Built 2001 Load: 33.6 t ADT: 180

STC 5804;LIONS DEN

Good

Over: CARIBOU CREEK

2.5S. 4.3W. BONNERS FERRY, Bonner, ID

Built 2018 Load: 33.7 t ADT: 300

FIR GROVE ROAD

Good

Over: CAMAS CREEK

3.6 S. 2.3 E. FAIRFIELD, Camas, ID

Built 2019 Load: 33.7 t ADT: 30

PARK ROAD

Good

Over: POTLATCH RIVER

1.9 S. 0.7 E. HELMER, Latah, ID

Built 2018 Load: 33.7 t ADT: 70

N2100E

Good

Over: CONSOLIDATED FARMERS CNL

2.7 W 2.5 S ST ANTHONY, Fremont, ID

Built 2014 Load: 33.7 t ADT: 140

N 3900 E; IONA RD

Good

Over: BURGESS CNL; SW RIGBY BR

0.5 S 0.4 W RIGBY, Jefferson, ID

Built 2013 Load: 33.7 t ADT: 3,000

WILLIAMS CREEK RD

Good

Over: SALMON RIVER; SHOUP BR

5.4 S. SALMON, Lemhi, ID

Built 2018 Load: 33.7 t ADT: 1,100

3236: RIVERWOOD RO

Good

Over: Little Wood River

0.5 mi S of US26, Lincoln, ID

Built 1999 Load: 33.7 t ADT: 25

FS ROUTE NO. 933

Good

Over: BEAVER CREEK

.01 MI FROM COUNTY RD 456, Shoshone, ID

Built 1985 Load: 33.7 t ADT: 50

FS ROUTE NO. 326

Good

Over: CLIFF CREEK

CLIFF CREEK, Shoshone, ID

Built 2010 Load: 33.7 t ADT: 40

NO DATA ENTERED

Good

Over: ELIZABETH CREEK

7 MI N OF KELLY FORKS WC, Clearwater, ID

Built 1954 Load: 33.7 t ADT: 80

NO DATA ENTERED

Good

Over: HIDDEN CREEK

12 MI FROM KELLY FORKS WC, Clearwater, ID

Built 2010 Load: 33.7 t ADT: 50

SUMMIT FLAT ROAD

Good

Over: GRIMES CREEK

5 MI SW OF PINE FLATS CG, Boise, ID

Built 1982 Load: 33.7 t ADT: 12

FDR

Good

Over: REDFISH LAKE CREEK

REDFISH LAKE OUTLET, Custer, ID

Built 2015 Load: 33.7 t ADT: 500

SH 6

Good

Over: GOLD CREEK

1.2 E. POTLATCH, Latah, ID

Built 2019 Load: 34.0 t ADT: 2,900

SH 6

Good

Over: SANTA CREEK; N. EMIDA BR

2.2 N. 2.7 E. EMIDA, Benewah, ID

Built 2020 Load: 34.0 t ADT: 710

STC 6760; RED RD

Good

Over: ST ANTHONY CANAL

1.1 N 1.0 W PARKER, Fremont, ID

Built 2020 Load: 34.0 t ADT: 490

N 5050 E

Good

Over: GREAT FEEDER CANAL HEAD

0.7 S. 0.4 W. HEISE, Jefferson, ID

Built 2016 Load: 34.0 t ADT: 40

BACK ROAD

Good

Over: WIMPEY CREEK

10.4 SE SALMON, Lemhi, ID

Built 2013 Load: 34.0 t ADT: 50

Showing 3,501-3,550 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.