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

TWENTY MILE CR RD

Good

Over: TWENTY MILE CREEK

7.0 S 3.0 W BONNERS FERR, Boundary, ID

Built 2007 Load: 30.8 t ADT: 130

KNIGHTON LN;3350 N

Good

Over: BIG LOST RIVER

2.3 N 0.5 E MOORE, Butte, ID

Built 2010 Load: 30.8 t ADT: 80

STC3895;YELLOWPINE

Good

Over: LUNCH CREEK

19 S. YELLOW PINE, Valley, ID

Built 1986 Load: 30.8 t ADT: 70

FDR 60055

Good

Over: NAPIAS CREEK

3 MILES N. OF COBALT ID, Lemhi, ID

Built 1974 Load: 30.8 t ADT: 50

LICK CREEK ROAD

Good

Over: LICK CREEK #2

13.2 NE MCCALL, Valley, ID

Built 2011 Load: 31.1 t ADT: 40

FS ROUTE NO. 396

Good

Over: MARBLE CREEK

MARBLE CREEK, Shoshone, ID

Built 1986 Load: 31.1 t ADT: 50

NO DATA ENTERED

Good

Over: QUARTZ CREEK

N FK CLW RD 247, Clearwater, ID

Built 1965 Load: 31.1 t ADT: 120

NO DATA ENTERED

Good

Over: FIX CREEK

9 MI FROM KELLY FORKS WC, Clearwater, ID

Built 2010 Load: 31.1 t ADT: 50

LONGHAUL ROAD

Good

Over: COTTONWOOD CREEK

8.0 N. 0.5 W. GRANGEVILLE, Idaho, ID

Built 2020 Load: 31.4 t ADT: 30

FS ROUTE 633

Good

Over: JIM CREEK

JIM CREEK, Boundary, ID

Built 2010 Load: 31.4 t ADT: 40

FS ROUTE 209

Good

Over: N.F. CDA RIVER

N.F. CDA RIVER, Kootenai, ID

Built 1958 Load: 31.4 t ADT: 40

MCCOY CREEK RD

Good

Over: IOWA CREEK

NO DATA ENTERED, Bonneville, ID

Built 1985 Load: 31.4 t ADT: 36

400 North Road

Good

Over: Main Northside Canal

4.0 N 9.3E. RUPERT, Minidoka, ID

Built 1980 Load: 31.6 t ADT: 120

I 86 EBL

Good

Over: PRIVATE RD.;MACHINE PASS

NEAR AMERICAN FALLS, Power, ID

Built 1959 Load: 31.8 t ADT: 4,050

US 20

Good

Over: I 15 NB-SB;JOHNS HOLE IC

IN IDAHO FALLS, Bonneville, ID

Built 1962 Load: 31.8 t ADT: 22,500

SH 31

Good

Over: RAINEY CREEK

IN SWAN VALLEY, Bonneville, ID

Built 2010 Load: 31.8 t ADT: 2,500

US 20

Good

Over: LOVING CREEK

11.6 W. CAREY, Blaine, ID

Built 1971 Load: 31.8 t ADT: 1,800

I 84 EBL

Good

Over: NOTUS CANAL

1.0 W. CALDWELL, Canyon, ID

Built 1964 Load: 31.8 t ADT: 21,500

I 84 EBL

Good

Over: CANYON CREEK

5.5 W. MOUNTAIN HOME, Elmore, ID

Built 1959 Load: 31.8 t ADT: 14,000

US 93

Good

Over: M CANAL

12.3 N. TWIN FALLS, Jerome, ID

Built 1984 Load: 31.8 t ADT: 6,500

STC 3784;E KUNA RD

Good

Over: NEW YORK CANAL

3.4 E. KUNA, Ada, ID

Built 1977 Load: 31.8 t ADT: 2,600

STC 1759; BLAZER

Good

Over: PORTNEUF RIVER

1.4 E. LAVA HOT SPRINGS, Bannock, ID

Built 2009 Load: 31.8 t ADT: 680

FRONTAGE ROAD

Good

Over: N CANAL

0.6 S. 0.9 W. JEROME, Jerome, ID

Built 1964 Load: 31.8 t ADT: 160

SHOSHONE STREET

Good

Over: RIDENBAUGH CANAL

IN BOISE;SHOSHONE ST, Ada, ID

Built 1989 Load: 31.8 t ADT: 1,400

E 49TH S

Good

Over: E.FK. SAND CREEK

1.0 S. 2.8 E. IDAHO FALLS, Bonneville, ID

Built 1977 Load: 31.8 t ADT: 3,600

E 49TH S

Good

Over: W.FK. SAND CREEK

1.0 S. 2.6 E. IDAHO FALLS, Bonneville, ID

Built 1978 Load: 31.8 t ADT: 3,600

HIGH TOP LANE

Good

Over: SALEM CANAL

2.0 N. 1.2 W. SUGAR CITY, Fremont, ID

Built 2017 Load: 31.8 t ADT: 130

N 2000 E

Good

Over: N.FK.TETON RIVER

1.5 N. SUGAR CITY, Madison, ID

Built 1976 Load: 31.8 t ADT: 1,700

W 10000 N

Good

Over: BADGER CREEK

0.5 S 2.5 E FELT, Teton, ID

Built 2012 Load: 31.8 t ADT: 100

SAVAGE PASS ROAD

Good

Over: BRIDGE CREEK

NO DATA ENTERED, Idaho, ID

Built 2008 Load: 31.8 t ADT: 40

SILVER CK. SMT. RD

Good

Over: SILVER CREEK

EGGERS CREEK CABIN, Valley, ID

Built 2010 Load: 31.8 t ADT: 50

SILVER CK. SMT. RD

Good

Over: SILVER CREEK

SILVER CK SUMMIT T.H., Valley, ID

Built 2010 Load: 31.8 t ADT: 50

ROAD

Good

Over: WARM RIVER

NO DATA ENTERED, Fremont, ID

Built 1980 Load: 31.8 t ADT: 36

STC3840;2ND FORK

Good

Over: SQUAW CREEK

4.5 N. OLA, Gem, ID

Built 2016 Load: 32.1 t ADT: 230

STIBNITE ROAD

Good

Over: PROFILE CREEK

3.1 E. YELLOW PINE, Valley, ID

Built 2011 Load: 32.1 t ADT: 30

FS ROUTE NO. 412

Good

Over: SHOSHONE CREEK

9 MI FROM SHOSHONE W.C., Shoshone, ID

Built 1977 Load: 32.1 t ADT: 50

FDR 662

Good

Over: HUGHES FORK

NO DATA ENTERED, Bonner, ID

Built 2016 Load: 32.1 t ADT: 50

NESBITT LANE

Good

Over: SQUAW CREEK

9.0 N 0.2 W OLA, Gem, ID

Built 2018 Load: 32.4 t ADT: 30

MAIN STREET

Good

Over: OROFINO CREEK

IN OROFINO; MAIN ST, Clearwater, ID

Built 1984 Load: 32.4 t ADT: 500

N 2500 E

Good

Over: TETON CANAL

0.8 N. 1.0 E. TETON, Fremont, ID

Built 1977 Load: 32.4 t ADT: 170

S 2ND WEST STREET

Good

Over: EGIN CANAL

IN ST ANTHONY, Fremont, ID

Built 2020 Load: 32.4 t ADT: 250

RATTLESNAKE CK RD

Good

Over: RATTLESNAKE CREEK (#2)

15.7 S. 3.1 N. SALMON, Lemhi, ID

Built 2019 Load: 32.4 t ADT: 20

FS ROUTE NO. 534

Good

Over: POTTER CREEK

POTTER CR ABOVE TRAIL CR, Kootenai, ID

Built 2010 Load: 32.4 t ADT: 40

FDR 447

Good

Over: PALOUSE RIVER

19 MILES FROM POTLATCH ID, Latah, ID

Built 2021 Load: 32.4 t ADT: 15

SH 8

Good

Over: RUBY CREEK

5.6 SE. BOVILL, Clearwater, ID

Built 1976 Load: 32.7 t ADT: 660

I 15 NBL

Good

Over: I 86 WB RAMP

2.7 N. POCATELLO, Bannock, ID

Built 2023 Load: 32.7 t ADT: 19,250

I 15 NBL & SBL

Good

Over: ROSS FORK CREEK

10.4 N. POCATELLO, Bingham, ID

Built 2023 Load: 32.7 t ADT: 29,000

US 20

Good

Over: PHYLLIS CANAL

9.6 E. CALDWELL, Ada, ID

Built 2023 Load: 32.7 t ADT: 19,500

STP 7343;MAIN ST

Good

Over: BOISE RIVER SLOUGH

IN BOISE;MAIN ST.WBL, Ada, ID

Built 1965 Load: 32.7 t ADT: 10,000

SH 50

Good

Over: I 84 EB-WB;KIMBERLY IC

8.9 E. TWIN FALLS, Jerome, ID

Built 2023 Load: 32.7 t ADT: 7,100

Showing 3,401-3,450 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.