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

I 90 EBL

Good

Over: SH 41

POST FALLS ECL, Kootenai, ID

Built 2023 Load: 32.7 t ADT: 32,250

US 93

Good

Over: CHALLIS CREEK

4.8 N. CHALLIS, Custer, ID

Built 1991 Load: 32.7 t ADT: 1,400

E LOCUST STREET

Good

Over: SNAKE RIVER VALLEY CANAL

IN SHELLY, Bingham, ID

Built 2023 Load: 32.7 t ADT: 500

STC2739;ROCK CR RD

Good

Over: ROCK CREEK

17.8 S. HANSON, Cassia, ID

Built 1971 Load: 32.7 t ADT: 590

NHS 8213;MIDDLETON

Good

Over: I 84; MIDDLETON RD. GS

3.2 W. NAMPA WCL, Canyon, ID

Built 2021 Load: 32.7 t ADT: 9,400

SNAKE RVR AVE RAMP

Good

Over: RAMP;SNAKE RIVER;HIGH BR

IN LEWISTON, Nez Perce, ID

Built 1982 Load: 32.7 t ADT: 5,550

I 15 NBL

Good

Over: CHUBBUCK ROAD

1.9 E. CHUBBUCK, Bannock, ID

Built 2023 Load: 32.7 t ADT: 11,750

STC7221;CARSON ST

Good

Over: PORTNEUF RIVER

IN POCATELLO;CARSON ST., Bannock, ID

Built 2023 Load: 32.7 t ADT: 4,500

NHS7983; USTICK RD

Good

Over: NOTUS CANAL

IN CALDWELL, Canyon, ID

Built 2023 Load: 32.7 t ADT: 10,000

JERICHO LOOP RD

Good

Over: ST CHARLES CREEK

0.9 W. ST. CHARLES, Bear Lake, ID

Built 2023 Load: 32.7 t ADT: 30

TIN CUP ROAD

Good

Over: TIN CUP CREEK

1.2 N. 4.5 E. WAYAN, Caribou, ID

Built 1989 Load: 32.7 t ADT: 10

MORMON RSVR ROAD

Good

Over: DRAIN

2.9 S. Fairfield, Camas, ID

Built 2023 Load: 32.7 t ADT: 110

2200 S ROAD

Good

Over: WEST CANAL

1.7 S. 1.5 W. OAKLEY, Cassia, ID

Built 2023 Load: 32.7 t ADT: 20

1700 SOUTH ROAD

Good

Over: BIG WOOD RIVER

1.0 N. 1.6 W. GOODING, Gooding, ID

Built 2023 Load: 32.7 t ADT: 280

S 1800 E

Good

Over: LITTLE WOOD RIVER

0.4 S. 1.0 W. GOODING, Gooding, ID

Built 2023 Load: 32.7 t ADT: 1,300

ARKOOSH ROAD

Good

Over: LITTLE WOOD RIVER

1.3 N 8.4 W. SHOSHONE, Lincoln, ID

Built 2023 Load: 32.7 t ADT: 30

4200 NORTH ROAD

Good

Over: DEEP CREEK

0.6 N. 4.4 W. BUHL, Twin Falls, ID

Built 2023 Load: 32.7 t ADT: 132

BROKEN HORN ROAD

Good

Over: DRY CREEK

2.6 N. 4.3 E. EAGLE, Ada, ID

Built 1987 Load: 32.7 t ADT: 50

S3760;FLTG FEATHER

Good

Over: MIDDLETON CANAL

1.0 N. 0.2 E. STAR, Ada, ID

Built 1988 Load: 32.7 t ADT: 4,400

S3760;FLTG FEATHER

Good

Over: MIDDLETON CANAL

1.0 N. 0.5 W. STAR, Ada, ID

Built 1966 Load: 32.7 t ADT: 4,800

VAN SLYKE ROAD

Good

Over: DEER FLAT CANAL

2.2 S. 3.0 E. WILDER, Canyon, ID

Built 1992 Load: 32.7 t ADT: 30

STC8315;LINCOLN RD

Good

Over: FIFTEEN MILE CREEK

0.5 N 5.0 E CALDWELL, Canyon, ID

Built 2005 Load: 32.7 t ADT: 220

S. 4TH AVENUE

Good

Over: INDIAN CREEK

IN CALDWELL; S 4TH AVE, Canyon, ID

Built 2023 Load: 32.7 t ADT: 470

STC8373;CANYON ST.

Good

Over: PHYLLIS CANAL

IN NAMPA, Canyon, ID

Built 2003 Load: 32.7 t ADT: 4,400

JAMES CREEK ROAD

Good

Over: ELK CREEK

5 N. ROCKY BAR, Elmore, ID

Built 2007 Load: 32.7 t ADT: 30

FLINT CREEK ROAD

Good

Over: N.FK.BOULDER CREEK

29.0 W. OREANA, Owyhee, ID

Built 2023 Load: 32.7 t ADT: 30

EASTSIDE DRIVE

Good

Over: N FK PAYETTE R(N BEACH)

6.6 N 2.0 E MCCALL, Valley, ID

Built 2023 Load: 32.7 t ADT: 100

BIG SALMON ROAD

Good

Over: LITTLE SALMON RIVER

RIGGINS SCL, Idaho, ID

Built 2010 Load: 32.7 t ADT: 60

BLUE HERON LANE

Good

Over: S.FK.PALOUSE RIVER

2.3 S. 1.8 W. MOSCOW, Latah, ID

Built 2000 Load: 32.7 t ADT: 50

SOUTH RIVER ROAD

Good

Over: PALOUSE RIVER

4.7 N. 0.8 E. V IOLA, Latah, ID

Built 2000 Load: 32.7 t ADT: 50

CHERRY LANE

Good

Over: CLEARWATER RIVER

2.4 E. MYRTLE, Nez Perce, ID

Built 2023 Load: 32.7 t ADT: 330

COUNTY RD; FR 754

Good

Over: SLAUGHTER HOUSE DRAW

0.5 N. 0.3 E. ST. JOE, Benewah, ID

Built 2023 Load: 32.7 t ADT: 230

DEER CREEK ROAD

Good

Over: SKIN CREEK

2.4E. 2.2N. MOYIE SPRINGS, Boundary, ID

Built 2023 Load: 32.7 t ADT: 50

LOWER GEM HILL RD

Good

Over: CANYON CREEK;GEM BR

0.1 S. 0.1 E.GEM, Shoshone, ID

Built 2023 Load: 32.7 t ADT: 50

SNAKE RIVER ROAD

Good

Over: FALL CREEK

1.5 W 3.5 S SWAN VALLEY, Bonneville, ID

Built 2008 Load: 32.7 t ADT: 20

E 121 ST S

Good

Over: IDAHO CANAL; HAMPTON BR

0.5 N 0.5 E TAYLORVILLE, Bonneville, ID

Built 2023 Load: 32.7 t ADT: 80

HIGBEE ST

Good

Over: BUTTE ARM CANAL

IN IDAHO FALLS:HIGBEE ST, Bonneville, ID

Built 2023 Load: 32.7 t ADT: 670

STC6867;GARDEN CRK

Good

Over: GARDEN CREEK

2.0 W. CHALLIS, Custer, ID

Built 2020 Load: 32.7 t ADT: 140

E 200 N

Good

Over: SALEM UNION CANAL

3.7 S 3.6 W ST ANTHONY, Fremont, ID

Built 2023 Load: 32.7 t ADT: 500

ISLAND PARK ACCESS

Good

Over: SALMON RIVER (ISLAND BR)

IN SALMON;ISLAND PARK, Lemhi, ID

Built 2016 Load: 32.7 t ADT: 120

NORTHWEST PASSAGE

Good

Over: SKI TRAIL

6.0 N. 3.5 W. SANDPOINT, Bonner, ID

Built 2023 Load: 32.7 t ADT: 100

S7227;POINTE PKWY

Good

Over: RIVERBEND AVE

AT POST FALLS WCL, Kootenai, ID

Built 2013 Load: 32.7 t ADT: 3,400

SMA9243;VICTORY RD

Good

Over: CALKINS LATERAL

2.5 S 1.9 W MERIDIAN, Ada, ID

Built 2016 Load: 32.7 t ADT: 3,800

S. CEMETERY ROAD

Good

Over: MILL SLOUGH

0.5 S. 0.4 W. MIDDLETON, Canyon, ID

Built 2021 Load: 32.7 t ADT: 50

PINE AVE

Good

Over: TEN MILE CREEK

0.3 W OF TEN MILE RD, Ada, ID

Built 2023 Load: 32.7 t ADT: 3,900

STC9573:E MALLARD

Good

Over: LOGGERS CREEK

IN BOISE; E.MALLARD DRIVE, Ada, ID

Built 2023 Load: 32.7 t ADT: 2,600

I 90 EBL

Good

Over: I 90 EB OFF RAMP

POST FALLS ECL, Kootenai, ID

Built 2023 Load: 32.7 t ADT: 32,250

I 90 EBL

Good

Over: I 90 EB ON RAMP

POST FALLS ECL, Kootenai, ID

Built 2023 Load: 32.7 t ADT: 32,250

FRD 5956

Good

Over: PACK CREEK

1 MILE EAST OF LOLO PASS, Idaho, ID

Built 2012 Load: 32.7 t ADT: 10

SPUR 653C

Good

Over: SEC.FK.CHIEF EAGLE EYE

2 MI NW SAGEHEN RSRVOIR, Gem, ID

Built 1980 Load: 32.7 t ADT: 15

Showing 3,451-3,500 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.