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

MULLAN AVE.

Fair

Over: CANYON CREEK

IN WALLACE CITY LIMITS, Shoshone, ID

Built 1987 Load: 32.7 t ADT: 50

ELIZABETH PARK RD

Fair

Over: S.FK.COEUR DALENE RIVER

0.4 S. 1.4 E. KELLOGG, Shoshone, ID

Built 1968 Load: 32.7 t ADT: 260

NORTHSIDE RD

Fair

Over: BIG CREEK;SE.CALDER BR

0.1 S. 3.7 E. CALDER, Shoshone, ID

Built 1960 Load: 32.7 t ADT: 50

STATELINE RD;WY16

Fair

Over: GRAND TETON CANAL

1 Mi West of Alta, Teton, ID

Built 2005 Load: 32.7 t ADT: 2,300

2800 N

Fair

Over: E.BRANCH BIG LOST RIVER

3.1 N. 2.2 W. ARCO, Butte, ID

Built 1920 Load: 32.7 t ADT: 40

OLD HWY 20

Fair

Over: PARKS LEWISVILLE CANAL

1.2 N. 0.8 E. RIGBY, Jefferson, ID

Built 1939 Load: 32.7 t ADT: 3,400

OLD SANTIAM ROAD

Fair

Over: S.FK. CLEARWATER RIVER

10 S. ELK CITY, Idaho, ID

Built 1934 Load: 32.7 t ADT: 10

S. PARK RIVER DR

Fair

Over: RIDENBAUGH CANAL

IN BOISE, Ada, ID

Built 1991 Load: 32.7 t ADT: 1,500

DEER CREEK ROAD

Fair

Over: BEAR VALLEY CREEK

21 N. LOWMAN, Valley, ID

Built 1971 Load: 32.7 t ADT: 30

FS ROUTE NO. 1514

Fair

Over: TEPEE CREEK

TEPEE CR, Shoshone, ID

Built 1974 Load: 32.7 t ADT: 50

NO DATA ENTERED

Fair

Over: BALL CREEK

BALL CREEK, Boundary, ID

Built 1963 Load: 32.7 t ADT: 50

NO DATA ENTERED

Fair

Over: LITTLE MOOSE CREEK

1.0 MI N OF OLD KELLY CR, Clearwater, ID

Built 1954 Load: 32.7 t ADT: 40

SPUR 348J

Fair

Over: PIKES FORK CREEK

NEAR NFSR 312/348J JUNCT, Boise, ID

Built 1985 Load: 32.7 t ADT: 10

SH 200

Fair

Over: BURLINGTON NORTHERN RR

3.6 W. CLARK FORK, Bonner, ID

Built 1966 Load: 33.0 t ADT: 1,900

FS ROUTE NO. 422

Fair

Over: BIG ELK CREEK

BIG ELK CREEK, Shoshone, ID

Built 1955 Load: 33.0 t ADT: 50

500N-1130E

Fair

Over: MAIN SOUTHSIDE CANAL

6.0 N. 2.9 E. DECLO, Cassia, ID

Built 1981 Load: 33.3 t ADT: 100

HEGLAR CANYON RD

Fair

Over: HEGLAR DRAIN

8.5 S. 4.5 E. RAFT RIVER, Cassia, ID

Built 1984 Load: 33.3 t ADT: 590

STC9123;ALLUMBAUGH

Fair

Over: RIDENBAUGH CANAL

IN BOISE;ALLUMBAUGH ST., Ada, ID

Built 1971 Load: 33.3 t ADT: 1,300

SMA 8683;BLACK CAT

Fair

Over: FIVE MILE CREEK

2.1 N. 3.1 W. MERIDIAN, Ada, ID

Built 1930 Load: 33.3 t ADT: 5,600

STC3718;PRPLE SAGE

Fair

Over: WILLOW CREEK

2.1 N. 0.9 E. MIDDLETON, Canyon, ID

Built 1975 Load: 33.3 t ADT: 1,900

N. CRANE ROAD

Fair

Over: CRANE CREEK

6.0 S. 14.7 E. MIDVALE, Washington, ID

Built 1982 Load: 33.3 t ADT: 50

E 81ST S

Fair

Over: E. BRANCH SAND CREEK

3.0 S. 1.9 W. AMMON, Bonneville, ID

Built 1964 Load: 33.3 t ADT: 150

US 95

Fair

Over: WEISER RIVER

9.4 N. COUNCIL NCL, Adams, ID

Built 2020 Load: 33.4 t ADT: 2,300

OLD COUNTY ROAD

Fair

Over: ST. MARIES RIVER

0.4 S. FERNWOOD, Benewah, ID

Built 2015 Load: 33.4 t ADT: 340

I 86 EBL

Fair

Over: YALE ROAD;RAFT RIVER IC

28.6 E. BURLEY, Cassia, ID

Built 1960 Load: 33.6 t ADT: 3,850

I 15 SBL

Fair

Over: MARKET LAKE CANAL

0.3 S. ROBERTS, Jefferson, ID

Built 1968 Load: 33.6 t ADT: 3,050

US 20

Fair

Over: I 84 EB-WB;PARMA IC

0.7 W. CALDWELL NWCL, Canyon, ID

Built 1964 Load: 33.6 t ADT: 6,200

US 20

Fair

Over: UPRR

IN IDAHO FALLS, Bonneville, ID

Built 1966 Load: 33.6 t ADT: 30,000

US 20

Fair

Over: SMA 7096;RIVERSIDE DR.IC

IN IDAHO FALLS;RIVERSIDE, Bonneville, ID

Built 1969 Load: 33.6 t ADT: 36,000

US 20 EBL

Fair

Over: SNAKE RIVER DRY BED CNL

2.3 N. RIGBY, Jefferson, ID

Built 1975 Load: 33.6 t ADT: 9,500

US 20 EBL

Fair

Over: MENAN CANAL

3.7 N. RIGBY, Jefferson, ID

Built 1975 Load: 33.6 t ADT: 9,500

US 20 WBL

Fair

Over: MENAN CANAL

3.7 N. RIGBY, Jefferson, ID

Built 1975 Load: 33.6 t ADT: 9,500

SMA 7643;HEALY RD

Fair

Over: NEW YORK CANAL

AT BOISE ECL;HEALY ROAD, Ada, ID

Built 1964 Load: 33.6 t ADT: 6,800

SH 21

Fair

Over: CANYON CREEK

24.5 NE. LOWMAN, Boise, ID

Built 1964 Load: 33.6 t ADT: 560

US 30

Fair

Over: I 84 WB-EB;W.BLISS IC

1.7 W. BLISS, Gooding, ID

Built 1974 Load: 33.6 t ADT: 740

STC3813;OLD ORE TR

Fair

Over: STC3816;OLD US 30;UPRR

2.0 S. MOUNTAIN HOME, Elmore, ID

Built 1973 Load: 33.6 t ADT: 3,000

SH 34

Fair

Over: COTTONWOOD CREEK

22 N. PRESTON, Franklin, ID

Built 1971 Load: 33.6 t ADT: 1,300

SH 34

Fair

Over: NORTH EXTENSION CANAL

1.9 N. GRACE, Caribou, ID

Built 1978 Load: 33.6 t ADT: 2,200

SH 44

Fair

Over: I 84 EB-WB;MIDDLETON IC

1.9 W. CALDWELL, Canyon, ID

Built 1964 Load: 33.6 t ADT: 28,000

SH 55

Fair

Over: WILSON DRAIN

2 W. NAMPA, Canyon, ID

Built 1973 Load: 33.6 t ADT: 24,000

US 20

Fair

Over: CHIMNEY CR.;SHEEP CR.

8.4 W. FAIRFIELD, Camas, ID

Built 1961 Load: 33.6 t ADT: 1,800

US 20

Fair

Over: CORRAL CREEK

6.8 W. FAIRFIELD, Camas, ID

Built 1969 Load: 33.6 t ADT: 1,800

US 20

Fair

Over: THREE MILE CREEK

4.8 W. FAIRFIELD, Camas, ID

Built 1969 Load: 33.6 t ADT: 1,800

SH 77

Fair

Over: MARSH CREEK

NEAR DECLO NCL, Cassia, ID

Built 1960 Load: 33.6 t ADT: 4,600

I 84 WBL

Fair

Over: FRONTAGE RD;GS NO.3

5.6 E. BLISS, Gooding, ID

Built 1977 Load: 33.6 t ADT: 9,250

I 84 EBL

Fair

Over: STC2744;MURTAUGH RD GS

18.5 W. BURLEY, Jerome, ID

Built 1966 Load: 33.6 t ADT: 11,750

I 84 WBL

Fair

Over: STC2744;MURTAUGH RD GS

18.5 W. BURLEY, Jerome, ID

Built 1966 Load: 33.6 t ADT: 11,750

I 90 EBL

Fair

Over: S.FK.COEUR DALENE RIVER

OSBURN WCL, Shoshone, ID

Built 1969 Load: 33.6 t ADT: 6,250

I 90 WBL

Fair

Over: S.FK.COEUR DALENE RIVER

OSBURN WCL, Shoshone, ID

Built 1969 Load: 33.6 t ADT: 6,250

I 90RAMPS BC & CD

Fair

Over: CANYON CREEK

IN WALLACE, Shoshone, ID

Built 1985 Load: 33.6 t ADT: 550

Showing 1,951-2,000 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.