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

CO. RD.;OLD US 93

Fair

Over: M CANAL

12.3 N. TWIN FALLS, Jerome, ID

Built 1934 Load: 29.0 t ADT: 5

500 WEST ROAD

Fair

Over: I 84;500 WEST RD GS

1.2 E. BURLEY, Minidoka, ID

Built 1961 Load: 29.0 t ADT: 150

1700 EAST RD

Fair

Over: HIGH LINE CANAL

5.7 S. 2.4 E. BUHL, Twin Falls, ID

Built 1981 Load: 29.0 t ADT: 400

STC2722;4100 N. RD

Fair

Over: DEEP CREEK

0.4 S. 4.3 W. BUHL, Twin Falls, ID

Built 1965 Load: 29.0 t ADT: 1,000

EIGHTEENTH STREET

Fair

Over: I 84;EIGHTEENTH ST GS

1.0 W. MOUNTAIN HOME, Elmore, ID

Built 1971 Load: 29.0 t ADT: 1,200

NICHOLES ROAD

Fair

Over: LAWYER CREEK;SW.KAMIAH B

1.2 S. 1.1 W. KAMIAH, Idaho, ID

Built 1950 Load: 29.0 t ADT: 130

E. OAK AVENUE

Fair

Over: COW CREEK

IN GENESEE, Latah, ID

Built 2005 Load: 29.0 t ADT: 50

STC 4811;LENVILLE

Fair

Over: LITTLE POTLATCH CREEK

4.5 N. 6.0 E. GENESEE, Latah, ID

Built 1973 Load: 29.0 t ADT: 110

HIGHLINE ARROW RD

Fair

Over: POTLATCH R(ARROW JCT BR)

2.2 N. 2.3 E. SPALDING, Nez Perce, ID

Built 1920 Load: 29.0 t ADT: 90

STC 7715;BRONX RD

Fair

Over: SAND CREEK

2.6 N. SANDPOINT NCL, Bonner, ID

Built 1980 Load: 29.0 t ADT: 700

THIRD STREET

Fair

Over: I 90 EB-WB;THIRD ST.GS

IN MULLAN;THIRD STREET, Shoshone, ID

Built 1973 Load: 29.0 t ADT: 360

JENSEN LANE

Fair

Over: WEST CAMAS CREEK

3.8 S. 0.5 W. KILGORE, Clark, ID

Built 2007 Load: 29.0 t ADT: 10

DIAMOND ROAD

Fair

Over: I 15 NB-SB;DIAMOND RD.GS

1.8 N. ROBERTS, Jefferson, ID

Built 1968 Load: 29.0 t ADT: 310

WILDHORSE CREEK RD

Fair

Over: WILDHORSE CREEK

17.0 N.E. SUN VALLEY, Custer, ID

Built 1970 Load: 29.0 t ADT: 25

LANDMARK/STANLEY

Fair

Over: ELK CREEK #1

7N 9E DEADWOOD RES, Valley, ID

Built 1961 Load: 29.0 t ADT: 30

LANDMARK/STANLEY

Fair

Over: ELK CREEK #2

7N 9E DEADWOOD RES, Valley, ID

Built 1961 Load: 29.0 t ADT: 30

W.AIRPORT WAY-DEPT

Fair

Over: W.AIRPORT WAY-ARRIVAL

AT BOISE AIRPORT, Ada, ID

Built 2004 Load: 29.0 t ADT: 4,000

FS ROUTE NO. 871

Fair

Over: E.F.CANUCK CR

EAST FORK CANUCK CREEK, Boundary, ID

Built 1990 Load: 29.2 t ADT: 50

FDR 5119

Fair

Over: ELDORADO CREEK

SNOW CR BRIDGE, Idaho, ID

Built 1963 Load: 29.2 t ADT: 10

FDR 100

Fair

Over: ELDORADO CREEK

ELDORADO CREEK, Idaho, ID

Built 1987 Load: 29.2 t ADT: 150

GUARD STATION RD.

Fair

Over: SLATE CREEK

SLATE CREEK, Idaho, ID

Built 1965 Load: 29.2 t ADT: 50

FOREST ROAD 421

Fair

Over: MALLARD CREEK

NO DATA ENTERED, Idaho, ID

Built 1992 Load: 29.2 t ADT: 50

FOREST ROAD 223

Fair

Over: GEDNEY CR

18 MI. FROM LOWELL ID, Idaho, ID

Built 1934 Load: 29.2 t ADT: 50

SMITH CREEK ROAD

Fair

Over: SMITH CREEK

3.4 MI. NE OF PRAIRIE, Elmore, ID

Built 1972 Load: 29.2 t ADT: 25

CUSTER MOTORWAY

Fair

Over: YANKEE FORK

NO DATA ENTERED, Custer, ID

Built 1962 Load: 29.2 t ADT: 100

BEAVER-LOON ROAD

Fair

Over: W.FK. MAYFIELD CREEK

NO DATA ENTERED, Custer, ID

Built 1968 Load: 29.2 t ADT: 10

BEAVER-LOON ROAD

Fair

Over: W. FK. MAYFIELD CREEK

NO DATA ENTERED, Custer, ID

Built 1967 Load: 29.2 t ADT: 10

JOHNSON CK - 50038

Fair

Over: JOHNSON CR

NO DATA ENTERED, Adams, ID

Built 1964 Load: 29.2 t ADT: 50

FDR

Fair

Over: SALMON RIVER

1 MILE WEST SVWC SNRA, Custer, ID

Built 1960 Load: 29.2 t ADT: 50

FS ROUTE NO. 442

Fair

Over: LOST CREEK

0.5 MI. FROM FH 208 JCT., Shoshone, ID

Built 1953 Load: 29.5 t ADT: 50

FS ROUTE NO. 413

Fair

Over: COPPER CREEK

COPPER CREEK, Kootenai, ID

Built 1975 Load: 29.5 t ADT: 50

FS ROUTE NO. 321

Fair

Over: MARBLE CREEK

MARBLE CREEK, Shoshone, ID

Built 1952 Load: 29.5 t ADT: 50

FS ROUTE NO. 311

Fair

Over: GRANITE CREEK

FORKS OF GRANITE, Bonner, ID

Built 1952 Load: 29.5 t ADT: 40

FS ROUTE NO. 1013

Fair

Over: LIME CREEK

LIME CREEK, Boundary, ID

Built 1964 Load: 29.5 t ADT: 40

FDR 1649

Fair

Over: LOCHSA RIVER

WLD GATEWAY CAMPGROUND, Idaho, ID

Built 1967 Load: 29.5 t ADT: 30

FOREST ROAD 1190

Fair

Over: TRAPPER CR

NO DATA ENTERED, Idaho, ID

Built 1958 Load: 29.5 t ADT: 40

STC4783;DENT BR RD

Fair

Over: N.FK.CLEARWATER;DENT BR

8.8N. 3.7E.OROFINO, Clearwater, ID

Built 1971 Load: 29.7 t ADT: 180

STC3833;EL PASO RD

Fair

Over: BLACK CANYON CANAL

1.2 S. 2.8 W. LETHA, Gem, ID

Built 1973 Load: 29.7 t ADT: 810

ROWLAND ROAD

Fair

Over: MARYS CREEK

4.5 S. 3.0 E. GRASMERE, Owyhee, ID

Built 1988 Load: 29.7 t ADT: 5

STC3857;SND HOLLOW

Fair

Over: FARMERS COOP CANAL

3.2S 2.4E NEW PLYMOUTH, Payette, ID

Built 1955 Load: 29.7 t ADT: 1,300

STC 8216;E 9TH ST

Fair

Over: GALLOWAY CANAL

0.4 N. 1.0 E. WEISER, Washington, ID

Built 1975 Load: 29.7 t ADT: 260

TOWNSHIP ROAD

Fair

Over: IDAHO CANAL

1.0 S. 1.5 E. IDAHO FALLS, Bonneville, ID

Built 1972 Load: 29.7 t ADT: 3,600

E 100 N

Fair

Over: TETON CANAL

0.9 N. 1.2 E. TETON, Fremont, ID

Built 1980 Load: 29.7 t ADT: 180

N 700 WEST STREET

Fair

Over: EGIN CANAL

IN ST ANTHONY;N.700W.ST, Fremont, ID

Built 1973 Load: 29.7 t ADT: 210

FS ROUTE NO. 437

Fair

Over: HAYDEN CREEK

HAYDEN CREEK, Kootenai, ID

Built 1953 Load: 29.8 t ADT: 50

FS ROUTE NO. 919

Fair

Over: S. LAVERNE CR

SOUTH LAVERNE CREEK, Kootenai, ID

Built 1973 Load: 29.8 t ADT: 50

FS ROUTE NO. 490

Fair

Over: BOULDER CREEK

BOULDER CREEK, Shoshone, ID

Built 1965 Load: 29.8 t ADT: 40

FDR 373

Fair

Over: BRUSHY FORK

33 MILES EA OF POWELL R S, Idaho, ID

Built 1957 Load: 29.8 t ADT: 40

FOREST ROAD 651

Fair

Over: OHARA CREEK

NO DATA ENTERED, Idaho, ID

Built 1958 Load: 29.8 t ADT: 50

NO DATA ENTERED

Fair

Over: LITTLE WEISER

NO DATA ENTERED, Adams, ID

Built 1953 Load: 29.8 t ADT: 50

Showing 1,551-1,600 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.