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 84

Fair

Over: MEADOW CREEK

5.7 E. SUBLETT, Cassia, ID

Built 1968 Load: 99.9 t ADT: 11,000

I 90 EBL & WBL

Fair

Over: CEDAR CREEK

11.6 E. COEUR DALENE, Kootenai, ID

Built 1988 Load: 99.9 t ADT: 14,500

I 90 EBL & WBL

Fair

Over: CEDAR CREEK

12.6 E. COEUR DALENE, Kootenai, ID

Built 1988 Load: 99.9 t ADT: 14,500

I 90 EBL & WBL

Fair

Over: CEDAR CREEK

12.7 E. COEUR DALENE, Kootenai, ID

Built 1988 Load: 99.9 t ADT: 14,500

US 95

Fair

Over: HATWAI CREEK

2.7 E. LEWISTON, Nez Perce, ID

Built 1979 Load: 99.9 t ADT: 5,500

US 95

Fair

Over: CALF CREEK

13.3 S. MOSCOW, Latah, ID

Built 2006 Load: 99.9 t ADT: 6,000

STC 1753;ARBON VLY

Fair

Over: BANNOCK CR.;S.PAULINE BR

0.5 S. PAULINE, Power, ID

Built 1962 Load: 99.9 t ADT: 110

STC 1829; PARKS RD

Fair

Over: DRAIN DITCH

0.3 S. 1.2 W. MORELAND, Bingham, ID

Built 1989 Load: 99.9 t ADT: 970

STC2748;EASTLAND

Fair

Over: ROCK CREEK

1.2 S. 1.0 E. TWIN FALLS, Twin Falls, ID

Built 1979 Load: 99.9 t ADT: 2,800

SMA7013;CLOVERDALE

Fair

Over: RIDENBAUGH CANAL

0.7S. 2.8E MERIDIAN, Ada, ID

Built 2005 Load: 99.9 t ADT: 19,000

STC 5759;DIVISION

Fair

Over: LITTLE PINE CREEK

1.0 N PINEHURST, Shoshone, ID

Built 1935 Load: 99.9 t ADT: 3,500

SMA 7124;E MAIN ST

Fair

Over: LINDSAY CREEK

IN LEWISTON, Nez Perce, ID

Built 1997 Load: 99.9 t ADT: 5,700

SMA7553;FEDERAL WY

Fair

Over: RIDENBAUGH CANAL

IN BOISE;FEDERAL WAY, Ada, ID

Built 1991 Load: 99.9 t ADT: 9,000

S 3200 E

Fair

Over: CUB RIVER;NE.FRANKLIN BR

1.2 N. 0.3 E. FRANKLIN, Franklin, ID

Built 1970 Load: 99.9 t ADT: 50

GRIFFIN LP(NORTH)

Fair

Over: W.BR.LITTLE WOOD RIVER

1.6 S. 0.2 E. CAREY, Blaine, ID

Built 1959 Load: 99.9 t ADT: 30

FIR GROVE ROAD

Fair

Over: CAMAS CREEK

3.4 S. 2.4 E. FAIRFIELD, Camas, ID

Built 1986 Load: 99.9 t ADT: 30

STP 3794;EAGLE RD

Fair

Over: FARR LATERAL CANAL

3.4 N. 3.3 E. KUNA, Ada, ID

Built 1993 Load: 99.9 t ADT: 1,900

SMA3340;MCDERMMOTT

Fair

Over: RIDENBAUGH HIGH LINE CNL

2.0 N. 2.7 W. KUNA, Canyon, ID

Built 1987 Load: 99.9 t ADT: 420

STC3928;S EAGLE RD

Fair

Over: MASON CREEK FEEDER CANAL

0.4 N. 3.3 E. KUNA, Ada, ID

Built 1990 Load: 99.9 t ADT: 1,100

SMA9213;VETERANS P

Fair

Over: BOISE RIVER;N CHANNEL

IN BOISE;VETERANS PARKWAY, Ada, ID

Built 1985 Load: 99.9 t ADT: 21,500

S3784;LOCUST GROVE

Fair

Over: FARR LATERAL CANAL

3.4 S. 0.9 E. MERIDIAN, Ada, ID

Built 1993 Load: 99.9 t ADT: 1,500

S3944;FARM TO MRKT

Fair

Over: WILLOW CREEK

0.5 N. 1.5 E. DONNELLY, Valley, ID

Built 1996 Load: 99.9 t ADT: 350

STC 3944;ELO ROAD

Fair

Over: LAKE FORK CANAL

2.1 S. 2.0 E. MCCALL, Valley, ID

Built 1996 Load: 99.9 t ADT: 1,400

BIG FLAT ROAD

Fair

Over: S.FK.CRANE CREEK

10.6 S. 8.8 E. MIDVALE, Washington, ID

Built 1991 Load: 99.9 t ADT: 50

ONAWAY ROAD

Fair

Over: GOLD CREEK

1.1 E. ONAWAY, Latah, ID

Built 1975 Load: 99.9 t ADT: 40

OLSON ROAD

Fair

Over: S.FK.PALOUSE RIVER

0.8 N. 3.0 E. MOSCOW, Latah, ID

Built 1970 Load: 99.9 t ADT: 30

US 95

Fair

Over: E.FK. LAPWAI CREEK

4.9 N. 1.0 E. WINCHESTER, Lewis, ID

Built 1957 Load: 99.9 t ADT: 3,500

FS ROUTE NO. 628

Good

Over: E.F. BOULDER

EAST FORK BOULDER, Boundary, ID

Built 2022 ADT: 50

NO DATA ENTERED

Good

Over: W.F. EMERALD

NO DATA ENTERED, Benewah, ID

Built 2020 ADT: 50

FS ROUTE NO. 419

Good

Over: RATTLE CREEK

RATTLE CREEK, Bonner, ID

Built 1953 ADT: 50

FDR 555

Good

Over: WEITAS CREEK

WEITAS GUARD STATION, Clearwater, ID

Built 1985 ADT: 10

FDR 377D

Good

Over: W FK POTLATCH CREEK

2 MI WEST OF ST HWY, Latah, ID

Built 1981 ADT: 5

FDR 382

Good

Over: ELK CREEK

8 MILES FROM ELK RIVER ID, Clearwater, ID

Built 2021 ADT: 10

FSR 360

Good

Over: HORSE CREEK

NEAR ELK SUMMIT CG, Idaho, ID

Built 2009 ADT: 50

NO DATA ENTERED

Good

Over: SILVER CREEK

NO DATA ENTERED, Valley, ID

Built 2009 ADT: 10

NO DATA ENTERED

Good

Over: SCRIVER CREEK

NO DATA ENTERED, Boise, ID

Built 2022 ADT: 50

MANN CK RD 50009

Good

Over: 4TH OF JULY CREEK

NO DATA ENTERED, Washington, ID

Built 2008 ADT: 50

NO DATA ENTERED

Good

Over: SUMMIT CREEK

NO DATA ENTERED, Idaho, ID

Built 1977 ADT: 50

NO DATA ENTERED

Good

Over: FOUR MILE CK

NO DATA ENTERED, Valley, ID

Built 1999 ADT: 50

DEEP CR. ROAD

Good

Over: DEEP CREEK

14 miles SW of Salmon ID, Lemhi, ID

Built 2008 ADT: 100

SHEEP CR. ROAD

Good

Over: SHEEP CREEK

NO DATA ENTERED, Lemhi, ID

Built 1985 ADT: 50

FDR 40135

Good

Over: ANTELOPE CREEK

ANTELOPE G.S., Butte, ID

Built 2007 ADT: 20

NO DATA ENTERED

Good

Over: NO DATA ENTERED

NO DATA ENTERED, Valley, ID

Built 2023 ADT: 50

FDR

Good

Over: EAST FORK SALMON RIVER

20 MILES FROM MOUTH OF R., Custer, ID

Built 1989 ADT: 50

FDR

Good

Over: EAST FORK SALMON RIVER

BOWERY GUARD STATION, Custer, ID

Built 1991 ADT: 50

FDR

Good

Over: HUCKELBERRY CREEK

3 MILES WEST SESSIONS LOE, Custer, ID

Built 1984 ADT: 50

FDR

Good

Over: VALLEY CREEK

NORTH MP120.7 ST HWY 21, Custer, ID

Built 1986 ADT: 60

FDR

Good

Over: POLE CREEK

2 MILES UP POLE CREEK ROD, Blaine, ID

Built 2013 ADT: 50

FDR

Good

Over: IRON CREEK

1.2 MILES UP FROM HWY 21, Custer, ID

Built 2012 ADT: 50

FDR

Good

Over: WILLOW CREEK

2 MILES EAST SHAKE CR G S, Elmore, ID

Built 1955 ADT: 50

Showing 3,001-3,050 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.