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

IRR BIA RTE 8

Good

Over: BLACKFOOT RIVER

9 KM E OF HWY 191&BLKFOOT, Bingham, ID

Built 1975 Load: 24.5 t ADT: 210

IRR BIA RTE 24

Good

Over: MAIN CANAL

4 KM EAST OF FORT HALL, Bingham, ID

Built 1969 Load: 24.5 t ADT: 820

IRR BIA RTE 24

Good

Over: LITTLE HANGMAN CREEK

9.6 KM SW OF AGENCY, Benewah, ID

Built 1998 Load: 24.5 t ADT: 25

US 20 EBL

Good

Over: TEXAS SLOUGH

AT THORNTON, Madison, ID

Built 1981 Load: 24.5 t ADT: 14,000

US 20 WBL

Good

Over: TEXAS SLOUGH

AT THORNTON, Madison, ID

Built 1981 Load: 24.5 t ADT: 14,000

US 20 26 RAMP

Good

Over: BOISE RVR SLOUGH;RAMP

BOISE;FAIRVIEW/CHINDEN IC, Ada, ID

Built 1991 Load: 24.5 t ADT: 6,500

STC 4719;DIXIE RD

Good

Over: S.FK.RED RIVER

10.6 S. 4.3 E. ELK CITY, Idaho, ID

Built 1965 Load: 24.5 t ADT: 110

OLD ADDIE ROAD

Good

Over: MOYIE RIVER (ADDIE BR)

0.1 N. 0.7 E. ADDIE, Boundary, ID

Built 1991 Load: 24.5 t ADT: 90

REDROCK LOOP

Good

Over: LITTLE LOST RIVER

NO DATA ENTERED, Custer, ID

Built 1966 Load: 24.6 t ADT: 10

20097

Good

Over: WARM RIVER

NO DATA ENTERED, Fremont, ID

Built 2015 Load: 24.6 t ADT: 50

FS ROUTE 2354

Good

Over: INK CREEK

NO DATA ENTERED, Shoshone, ID

Built 2010 Load: 24.9 t ADT: 40

FRD 5671

Good

Over: PACK CREEK

10 MINS S OF LOLO PASS, Idaho, ID

Built 2012 Load: 24.9 t ADT: 10

SAND CREEK ROAD

Good

Over: SAND CREEK

2 MI E LANDMARK AIRSTRIP, Valley, ID

Built 1976 Load: 24.9 t ADT: 5

BLAINE ST

Good

Over: PARADISE CREEK

IN MOSCOW;BLAINE AT WHITE, Latah, ID

Built 1972 Load: 25.2 t ADT: 3,200

NORTH 4850 EAST RD

Good

Over: ANDERSON CANAL

0.1 N. 2.0 E. RIRIE, Jefferson, ID

Built 1974 Load: 25.2 t ADT: 20

N 2900 E RD

Good

Over: BUTTE MARKET LAKE CANAL

1.0 N. 0.2 E. ROBERTS, Jefferson, ID

Built 1974 Load: 25.2 t ADT: 30

N 3600 E RD

Good

Over: BURGESS CANAL

1.1 S. 3.4 W. RIGBY, Jefferson, ID

Built 1967 Load: 25.2 t ADT: 290

SMA 3824;BNKS LWMN

Good

Over: M.FK.PAYETTE R;CROUCH BR

0.8 W CROUCH, Boise, ID

Built 2013 Load: 25.3 t ADT: 2,200

S. RAYMOND ROAD

Good

Over: PORTNEUF MARSH VALLY CNL

3.7 N. 0.3 E. ARIMO, Bannock, ID

Built 2019 Load: 25.3 t ADT: 100

3043: WARM SPRING

Good

Over: Big Timber Creek

5 mi W of ID28, Lemhi, ID

Built 1979 Load: 25.3 t ADT: 25

FS ROUTE NO. 2730

Good

Over: CONSULAS CREEK

CONSALUS CREEK, Bonner, ID

Built 2010 Load: 25.3 t ADT: 40

SMITH CK. SPUR E

Good

Over: SMITH CREEK

.1 MI. SO. RD. 175, Elmore, ID

Built 1986 Load: 25.3 t ADT: 5

WAPITI ROAD

Good

Over: SOUTH FORK PAYETTE RIVER

WAPITI CR SUMMER HOME, Boise, ID

Built 1976 Load: 25.3 t ADT: 25

I 86 EBL

Good

Over: FALL CREEK

16.2 W. AMERICAN FALLS, Power, ID

Built 1981 Load: 25.4 t ADT: 3,850

I 86 WBL

Good

Over: FALL CREEK

16.2 W. AMERICAN FALLS, Power, ID

Built 1981 Load: 25.4 t ADT: 3,850

US 20

Good

Over: BIG LOST RIVER

16.4 E. ARCO, Butte, ID

Built 1977 Load: 25.4 t ADT: 2,600

STC6715(N 3400 E)

Good

Over: BURGESS CANAL

3.9 S. 0.5 W. LEWISVILLE, Jefferson, ID

Built 1960 Load: 25.4 t ADT: 3,100

FOUNDRY ROAD

Good

Over: SAND CREEK

2.0 S. 2.0 E. SHELLEY, Bingham, ID

Built 1989 Load: 25.4 t ADT: 135

MUNDY GULCH ROAD

Good

Over: LITTLE WEISER RIVER

0.7 W. INDIAN VALLEY, Adams, ID

Built 1981 Load: 25.4 t ADT: 100

STC3821;OLD HWY 30

Good

Over: ALKALI CREEK

3.0 W. GLENNS FERRY, Elmore, ID

Built 1977 Load: 25.4 t ADT: 970

OASIS ROAD

Good

Over: D LINE CANAL

11.5S. 2.6E. NEW PLYMOUTH, Payette, ID

Built 2000 Load: 25.4 t ADT: 680

N 1700 E

Good

Over: ST. ANTHONY CANAL

1.2 N. 1.1 E. EGIN, Fremont, ID

Built 1996 Load: 25.4 t ADT: 100

N 3470 E RD

Good

Over: DRY BED CANAL;MIDWAY BR.

1.0 S. 0.2 W. MENAN, Jefferson, ID

Built 1977 Load: 25.4 t ADT: 350

N 3980 EAST ROAD

Good

Over: DRY BED

1.8 N. 0.3 E. RIGBY, Jefferson, ID

Built 1992 Load: 25.4 t ADT: 100

2502: LYONS BAR

Good

Over: White Bird Creek

0.5 mi W of US95, Idaho, ID

Built 2000 Load: 25.6 t ADT: 25

FS ROUTE NO. 760

Good

Over: LITTLE NF CLEARWATER

LITTLE NF CLEARWATER, Shoshone, ID

Built 2006 Load: 25.6 t ADT: 40

FS ROUTE NO. 812

Good

Over: BIG ELK CREEK

TEPEE CREEK, Shoshone, ID

Built 1952 Load: 25.6 t ADT: 40

FS ROUTE NO. 633

Good

Over: PEAK CREEK

PEAK CREEK, Boundary, ID

Built 1955 Load: 25.6 t ADT: 40

DRY BUCK-BURNT CK.

Good

Over: EAST FORK FALL CREEK

1.8 MI W. OF RED MOUNTAIN, Elmore, ID

Built 2010 Load: 25.6 t ADT: 50

ROADWAY

Good

Over: BRUSH CREEK

4 MI SSW OF LAKE CASCADE, Valley, ID

Built 1984 Load: 25.6 t ADT: 12

DEADWD. RESV. RD.

Good

Over: WILD BUCK CREEK

1 MI N DEADWOOD RESRVIOR, Valley, ID

Built 1975 Load: 25.6 t ADT: 12

STANLEY-WARM LAKE

Good

Over: FIR CREEK

2 MI E. OF BRUCE MEADOWS, Valley, ID

Built 2009 Load: 25.6 t ADT: 50

FDR

Good

Over: BAKER CREEK

5 MILES UP BAKER CREEK, Blaine, ID

Built 1964 Load: 25.6 t ADT: 100

FOREST ROAD 1803

Good

Over: RED RIVER

2 MI. FROM ELK CITY, Idaho, ID

Built 1967 Load: 25.9 t ADT: 40

DEADWD. RESV. RD.

Good

Over: BASIN CREEK

.1 MI N DEADWOOD RESRVOIR, Valley, ID

Built 1975 Load: 25.9 t ADT: 12

RAMMAGE MEADOWS RD

Good

Over: THIRD FK.CHIEF EAGLE EYE

THIRD FORK CABIN, Gem, ID

Built 1963 Load: 25.9 t ADT: 20

LUNCH CK. FLAT RD.

Good

Over: LUNCH CREEK

2 MI NW LANDMARK AIRSTRIP, Valley, ID

Built 1980 Load: 26.2 t ADT: 5

MCCOY CREEK ROAD

Good

Over: MCCOY CREEK

NO DATA ENTERED, Bonneville, ID

Built 1986 Load: 26.2 t ADT: 36

I 86 WBL

Good

Over: ISAAK LOOP GS

4.6 W. AMERICAN FALLS, Power, ID

Built 1984 Load: 26.3 t ADT: 3,900

SH 21

Good

Over: CANYON CREEK

25 NE. LOWMAN, Boise, ID

Built 1964 Load: 26.3 t ADT: 560

Showing 3,151-3,200 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.