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

LEVEL C ROAD

Good

Over: E. FORK HAYDEN CREEK

NO DATA ENTERED, Lemhi, ID

Built 1974 Load: 29.2 t ADT: 10

OLD CHILLY RD

Good

Over: BIG LOST RIVER

9.6 N 12.7 W MACKAY, Custer, ID

Built 2023 Load: 29.5 t ADT: 40

STIBNITE ROAD

Good

Over: E FK OF S FK SALMON RVR

8.0 E YELLOW PINE, Valley, ID

Built 2012 Load: 29.5 t ADT: 30

FS ROAD 5112

Good

Over: LOLO CREEK

BRADFORD BRIDGE, Clearwater, ID

Built 2010 Load: 29.5 t ADT: 10

CLEAR CREEK ROAD

Good

Over: M. FORK PAYETTE RIVER

14 MI SW OF WARM LAKE, Valley, ID

Built 1963 Load: 29.5 t ADT: 12

NO DATA ENTERED

Good

Over: LAKE CREEK

NO DATA ENTERED, Idaho, ID

Built 2001 Load: 29.5 t ADT: 50

STC 6760;S 3300 W

Good

Over: TEXAS SLOUGH;W.THORNTON

0.1 S. 0.3 W. THORNTON, Madison, ID

Built 1981 Load: 29.7 t ADT: 390

STC 4707;OLD HWY95

Good

Over: WHITE BIRD CREEK

0.3 S. WHITE BIRD, Idaho, ID

Built 2013 Load: 29.8 t ADT: 570

SANDPIPER WAY

Good

Over: W FK SAND CREEK

1.4 S 2.3 E IDAHO FALLS, Bonneville, ID

Built 2021 Load: 29.8 t ADT: 100

1920: DARLING CREE

Good

Over: Challis Creek

0.3 mi N of Challis Cr Rd, Custer, ID

Built 1981 Load: 29.8 t ADT: 25

FS ROUTE NO. 2567

Good

Over: BEAVER CREEK

BEAVER CREEK, Boundary, ID

Built 1979 Load: 29.8 t ADT: 50

FOREST ROAD 492

Good

Over: SO FK CLEARWATER RV

SANTIAM, Idaho, ID

Built 1980 Load: 29.8 t ADT: 50

Dam Crest Road

Good

Over: ANDERSON RANCH DAM SPWY

ANDERSON RANCH DAM, Elmore, ID

Built 1950 Load: 29.9 t ADT: 50

I 86 WBL

Good

Over: PRIVATE RD.;MACHINE PASS

NEAR AMERICAN FALLS, Power, ID

Built 1959 Load: 29.9 t ADT: 4,050

I 15 SBL

Good

Over: SAMARIA ROAD GS

6.8 S. MALAD, Oneida, ID

Built 1975 Load: 29.9 t ADT: 6,250

SH 19

Good

Over: GOLDEN GATE CANAL

0.7 SE WILDER SCL, Canyon, ID

Built 1976 Load: 29.9 t ADT: 7,500

I 84 EBL

Good

Over: WHITLEY ROAD GS

2.0 E. OREGON-IDAHO LINE, Payette, ID

Built 1960 Load: 29.9 t ADT: 13,000

SH 75

Good

Over: SALMON RIVER;SLATE CR BR

9.0 W. CLAYTON, Custer, ID

Built 2011 Load: 29.9 t ADT: 660

STC 3904;WARM LK

Good

Over: S.FK.SALMON RIVER

9.4 N. 16.8 E. CASCADE, Valley, ID

Built 1960 Load: 29.9 t ADT: 370

STC4782;GRANGEMONT

Good

Over: WHISKEY CREEK;STANTON BR

0.7 N. 2.8 E. OROFINO, Clearwater, ID

Built 1954 Load: 29.9 t ADT: 1,800

MONTE VISTA DRIVE

Good

Over: I 15;MONTE VISTA DR GS

IN POCATELLO, Bannock, ID

Built 1997 Load: 29.9 t ADT: 2,200

STC 1759;OLD HW 30

Good

Over: DRAIN DITCH

AT BANCROFT, Caribou, ID

Built 1976 Load: 29.9 t ADT: 150

2400 E

Good

Over: I 84;EIRR;2400 E GS

3.8 W. JEROME, Gooding, ID

Built 1971 Load: 29.9 t ADT: 70

STC 5748; W ELDER

Good

Over: BOZARD CREEK

8.4 N. 5.3 W. WORLEY, Kootenai, ID

Built 1955 Load: 29.9 t ADT: 700

N 85TH E

Good

Over: WILLOW CREEK

3.1 S. 5.0 W. RIRIE, Bonneville, ID

Built 1993 Load: 29.9 t ADT: 170

E 1900 N

Good

Over: I 15 NB-SB;E 1900 N GS

1.8 S. HAMER, Jefferson, ID

Built 1960 Load: 29.9 t ADT: 80

SUNNYSIDE BENCH

Good

Over: WHEELER CANYON CREEK

0.8 N. 1.0 E. LENORE, Nez Perce, ID

Built 2013 Load: 30.1 t ADT: 90

SMA 9793; MAIN ST

Good

Over: BOISE VRT CENTER

MAIN ST EAST OF 8TH ST, Ada, ID

Built 2016 Load: 30.1 t ADT: 6,000

FS ROUTE NO. 1309

Good

Over: MYRTLE CREEK

MYRTLE CREEK, Boundary, ID

Built 1981 Load: 30.1 t ADT: 50

MIDDLE FK PAYETTE

Good

Over: RATTLESNAKE CREEK

.2 MI N RATTLESNAKE CK CG, Valley, ID

Built 2009 Load: 30.1 t ADT: 50

SANDS CANYON RD

Good

Over: LITTLE LOST RIVER

NO DATA ENTERED, Custer, ID

Built 1987 Load: 30.1 t ADT: 5

FDR

Good

Over: HYNDMAN CREEK

8 MILES EAST OF KETCHUM, Blaine, ID

Built 1985 Load: 30.1 t ADT: 30

OLD HWY ROAD

Good

Over: SHE CREEK

0.6 N 2.4 E MIDVALE, Washington, ID

Built 2018 Load: 30.5 t ADT: 90

1979: OLD STAGE

Good

Over: Morgan Creek

5 mi N of US93, Custer, ID

Built 2004 Load: 30.5 t ADT: 25

FS ROUTE NO. 435

Good

Over: KENO CREEK

KENO CREEK, Boundary, ID

Built 2011 Load: 30.5 t ADT: 40

FS ROUTE NO.760

Good

Over: LITTLE LOST LAKE CREEK

LITTLE LOST LAKE, Shoshone, ID

Built 2006 Load: 30.5 t ADT: 40

FS ROUTE #2646

Good

Over: SNOW CREEK

10 MI. FROM BONNERS FERRY, Boundary, ID

Built 1980 Load: 30.5 t ADT: 40

NO DATA ENTERED

Good

Over: RAWHIDE CREEK

22 MI FROM KELLY FORKS WC, Clearwater, ID

Built 2010 Load: 30.5 t ADT: 100

FDR382

Good

Over: ELK CREEK

8 MILES FROM ELK RIVER, Clearwater, ID

Built 2017 Load: 30.5 t ADT: 20

I 15 NBL

Good

Over: ROBIN RD GS

2.8 S. MCCAMMON, Bannock, ID

Built 1964 Load: 30.8 t ADT: 6,500

I 15 SBL

Good

Over: ROBIN RD GS

2.8 S. MCCAMMON, Bannock, ID

Built 1964 Load: 30.8 t ADT: 6,500

I 15 SBL

Good

Over: GIBSON CANAL

5.5 S. BLACKFOOT, Bingham, ID

Built 1959 Load: 30.8 t ADT: 13,000

SH 39

Good

Over: HIGHLINE CANAL

8.9 N. ABERDEEN, Bingham, ID

Built 1977 Load: 30.8 t ADT: 970

SH 51

Good

Over: WEST BRUNEAU RVR SLOUGH

1.0 W. BRUNEAU, Owyhee, ID

Built 1955 Load: 30.8 t ADT: 1,200

I 84 WBL

Good

Over: WHITLEY ROAD GS

2.0 E. OREGON-IDAHO LINE, Payette, ID

Built 1960 Load: 30.8 t ADT: 13,000

STC3907; DEINHARD

Good

Over: N. FK. PAYETTE RIVER

IN MCCALL, Valley, ID

Built 2005 Load: 30.8 t ADT: 3,300

STP 7073;COLE RD

Good

Over: RIDENBAUGH CANAL;COLE GS

0.7 W. BOISE WCL;COLE RD, Ada, ID

Built 1968 Load: 30.8 t ADT: 14,000

STC 7393;OWYHEE ST

Good

Over: NEW YORK CANAL

OWYHEE STREET IN BOISE, Ada, ID

Built 1997 Load: 30.8 t ADT: 2,100

BROADFORD ROAD

Good

Over: BIG WOOD RIVER

1.8 N. 1.7 W. BELLEVUE, Blaine, ID

Built 1985 Load: 30.8 t ADT: 660

GENESEE-TROY ROAD

Good

Over: MIDDLE POTLATCH CREEK

0.8 S. 0.8 E. JOEL, Latah, ID

Built 1994 Load: 30.8 t ADT: 200

Showing 3,351-3,400 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.