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 90 EBL

Fair

Over: CDA LAKE;BLUE CREEK BAY

7.7 E. COEUR DALENE, Kootenai, ID

Built 1972 Load: 39.0 t ADT: 8,750

I 90 EBL

Fair

Over: STC 5756;BIG CREEK RD IC

2.6 W. OSBURN, Shoshone, ID

Built 1969 Load: 39.0 t ADT: 6,750

I 90 WBL

Fair

Over: STC 5756;BIG CREEK RD IC

2.6 W. OSBURN, Shoshone, ID

Built 1969 Load: 39.0 t ADT: 6,750

I 90 EBL

Fair

Over: STC 5766;JOHNSON ST.GS

IN OSBURN;JOHNSON STREET, Shoshone, ID

Built 1969 Load: 39.0 t ADT: 6,250

I 90 WBL

Fair

Over: STC 5766;JOHNSON ST.GS

IN OSBURN;JOHNSON STREET, Shoshone, ID

Built 1969 Load: 39.0 t ADT: 6,250

I 90 EB & WB

Fair

Over: S.FK.CDA R;FR.RD.

1.9 W. WALLACE, Shoshone, ID

Built 1978 Load: 39.0 t ADT: 11,000

I 90 EBL & WBL

Fair

Over: I 90 EB OFF;W.MULLAN IC

MULLAN SCL, Shoshone, ID

Built 1973 Load: 39.0 t ADT: 9,600

US 91

Fair

Over: ROSS FORK CREEK

0.5 S. FORT HALL, Bingham, ID

Built 1925 Load: 39.0 t ADT: 4,000

SH 87

Fair

Over: TARGHEE CREEK

10.2 N. MACKS INN, Fremont, ID

Built 2006 Load: 39.0 t ADT: 2,400

STC2754;S. LINCOLN

Fair

Over: N CANAL

3.5 S. JEROME, Jerome, ID

Built 1983 Load: 39.0 t ADT: 5,700

STC2757;NORTH ROAD

Fair

Over: S CANAL

2.5 N. JEROME, Jerome, ID

Built 1999 Load: 39.0 t ADT: 1,800

STC 3894;CUPRUM RD

Fair

Over: WEISER RIVER;COUNCIL BR.

0.2 N. 0.5 W. COUNCIL, Adams, ID

Built 1956 Load: 39.0 t ADT: 190

STC 3894;CUPRUM RD

Fair

Over: BEAR CREEK

2.8N. 19.3W. NEW MEADOWS, Adams, ID

Built 1969 Load: 39.0 t ADT: 80

STC 5804;WESTSIDE

Fair

Over: FISHER CREEK

1.5S. 2.9W. COPELAND, Boundary, ID

Built 2003 Load: 39.0 t ADT: 300

STC 5804;COPELAND

Fair

Over: KOOTENAI R.;COPELAND BR.

0.1 N. 1.3 W. COPELAND, Boundary, ID

Built 1969 Load: 39.0 t ADT: 300

S6805;YALE-KILGORE

Fair

Over: HENRYS FK SNAKE R;MCCREA

2.4 S. 3.2 W. MACKS INN, Fremont, ID

Built 1995 Load: 39.0 t ADT: 2,000

SMA 7721;RIVERTON

Fair

Over: I 15;RIVERTON ROAD GS

1.3 S. BLACKFOOT, Bingham, ID

Built 1962 Load: 39.0 t ADT: 900

BASELINE RD;1200 N

Fair

Over: GREAT WESTERN CANAL

1.0 S 3.2 W SHELLEY, Bingham, ID

Built 2001 Load: 39.0 t ADT: 190

NIPPER ROAD

Fair

Over: DOWNY MARSH VALLEY CNL

5.6 N. 3.1 W. BANCROFT, Caribou, ID

Built 1986 Load: 39.0 t ADT: 50

SMA9783;LOCUST GRV

Fair

Over: I 84;LOCUST GROVE GS

1.8 SE MERIDIAN, Ada, ID

Built 2008 Load: 39.0 t ADT: 19,500

SMA3683;BLACK CAT

Fair

Over: INDIAN CREEK

2.2 N. 1.7 W. KUNA, Ada, ID

Built 1989 Load: 39.0 t ADT: 1,100

SUMMIT FLAT ROAD

Fair

Over: SMITH CREEK

0.5 E. PIONEERVILLE, Boise, ID

Built 1974 Load: 39.0 t ADT: 50

RIM ROAD

Fair

Over: MORA CANAL

7.0 S. 3.6 W. NAMPA, Canyon, ID

Built 1995 Load: 39.0 t ADT: 140

STC 7185;APPLEWAY

Fair

Over: APPLEWAY PED OP

IN COEUR DALENE;APPLEWAY, Kootenai, ID

Built 1971 Load: 39.0 t ADT: 3,500

STC 5736;HAYDEN LK

Fair

Over: HAYDEN CREEK

3.5 N. 2.9 E. HAYDEN LAKE, Kootenai, ID

Built 1987 Load: 39.0 t ADT: 2,400

N 3800 E

Fair

Over: FALL RIVER

1.6 S. 2.8 E. ASHTON, Fremont, ID

Built 1995 Load: 39.0 t ADT: 25

N 175 E RD

Fair

Over: EAGLE ROCK CNL HEADGATE

0.2 S. 4.4 E. RIRIE, Jefferson, ID

Built 1997 Load: 39.0 t ADT: 40

N YELLOWSTONE HWY

Fair

Over: DRY BED CANAL

1.7 N. 1.2 E. RIGBY, Jefferson, ID

Built 1999 Load: 39.0 t ADT: 3,400

ELK SUMMIT RD

Fair

Over: UPPER ELK CREEK

13.0 N 3.8 W YELLOW PINE, Valley, ID

Built 2003 Load: 39.0 t ADT: 15

ELK SUMMIT RD

Fair

Over: LOWER ELK CREEK

13.1 N 4.5 W YELLOW PINE, Valley, ID

Built 2003 Load: 39.0 t ADT: 15

CLEAR CREEK RD

Fair

Over: CLEAR CREEK

3.5 W 8.3 S CASCADE, Valley, ID

Built 1966 Load: 39.0 t ADT: 60

CLEAR CREEK RD

Fair

Over: CLEAR CREEK

4.3 W 7.7 S CASCADE, Valley, ID

Built 1966 Load: 39.0 t ADT: 60

YANKEE FORK ROAD

Fair

Over: YANKEE FORK CREEK

1.1 N 0.7 E of SUNBEAM, Custer, ID

Built 1966 Load: 39.0 t ADT: 200

FS ROUTE NO. 208

Fair

Over: BRETT CREEK

21.1 MI. FROM BAVINS JCT., Shoshone, ID

Built 1974 Load: 39.2 t ADT: 40

FDR 250

Fair

Over: LONG CREEK

CEDARS- 30 MI SW OF SUP, Clearwater, ID

Built 1948 Load: 39.5 t ADT: 50

FOREST ROAD 651

Fair

Over: OHARA CREEK

NO DATA ENTERED, Idaho, ID

Built 1958 Load: 39.5 t ADT: 50

PEBBLE CREEK ROAD

Fair

Over: PORTNEUF R;PEBBLE BR

1.6 N. 5.5 W. BANCROFT, Caribou, ID

Built 1984 Load: 39.6 t ADT: 115

STC5731;ST JOE RVR

Fair

Over: EAGLE CREEK

2.7 S. 11.7 E. AVERY, Shoshone, ID

Built 1992 Load: 39.6 t ADT: 300

SH 11

Fair

Over: QUARTZ CREEK;THREE MILE

1.8 N. PIERCE, Clearwater, ID

Built 1972 Load: 39.9 t ADT: 200

SH 13

Fair

Over: S.F.CLEARWATER;HARPSTER

1.1 S. HARPSTER, Idaho, ID

Built 1985 Load: 39.9 t ADT: 1,200

I 86 EBL

Fair

Over: UPRR;POCATELLO AIRPORT

6.1 W. CHUBBUCK, Power, ID

Built 1968 Load: 39.9 t ADT: 6,500

I 86 WBL

Fair

Over: UPRR;POCATELLO AIRPORT

6.1 W. CHUBBUCK, Power, ID

Built 1968 Load: 39.9 t ADT: 6,500

I 86 EBL

Fair

Over: UPRR;CHUBBUCK OVERPASS

0.4 E. CHUBBUCK, Bannock, ID

Built 1963 Load: 39.9 t ADT: 12,750

I 15 NBL

Fair

Over: W.BRIDGE ST.GS;UPRR OP

0.3 S. BLACKFOOT, Bingham, ID

Built 1962 Load: 39.9 t ADT: 12,500

I 15 SBL

Fair

Over: W.BRIDGE ST.GS;UPRR OP

0.3 S. BLACKFOOT, Bingham, ID

Built 1962 Load: 39.9 t ADT: 12,500

US 20

Fair

Over: WILLOW CREEK

3 N. IDAHO FALLS, Bonneville, ID

Built 1970 Load: 39.9 t ADT: 26,000

US 20

Fair

Over: BUFFALO RIVER;PONDS BR.

5.7 S. MACKS INN, Fremont, ID

Built 1975 Load: 39.9 t ADT: 6,400

US 20

Fair

Over: HENRYS FK. SNAKE RIVER

AT MACKS INN, Fremont, ID

Built 1975 Load: 39.9 t ADT: 6,400

I 84B

Fair

Over: PHYLLIS CANAL

IN NAMPA, Canyon, ID

Built 1970 Load: 39.9 t ADT: 16,000

SH 48

Fair

Over: BURGESS CANAL

6.4 E. RIGBY, Jefferson, ID

Built 1986 Load: 39.9 t ADT: 2,000

Showing 2,451-2,500 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.