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

US 12

Fair

Over: CLWATER R.;NPRR;ARROW BR

10.4 E. LEWISTON, Nez Perce, ID

Built 1972 Load: 21.8 t ADT: 4,700

SMA 7643;ECKERT RD

Fair

Over: BOISE RIVER(BARBER BR)

AT BOISE ECL;ECKERT RD, Ada, ID

Built 1954 Load: 21.8 t ADT: 6,500

SH 21

Fair

Over: MORES CR;LUCKY PEAK RES.

17 N. BOISE, Ada, ID

Built 1953 Load: 21.8 t ADT: 3,500

SH 21

Fair

Over: S.FK.PAYETTE R;LOWMAN BR

AT LOWMAN, Boise, ID

Built 1948 Load: 21.8 t ADT: 390

I 84B NBL

Fair

Over: SNAKE RIVER;HEYBURN BR.

AT BURLEY NCL, Cassia, ID

Built 1955 Load: 21.8 t ADT: 7,750

SH 33

Fair

Over: S.FK.TETON RIVER

IN REXBURG, Madison, ID

Built 1971 Load: 21.8 t ADT: 17,000

I 90RAMP EB OFF

Fair

Over: PINE CREEK;EB OFF RAMP

5.1 W. KELLOGG, Shoshone, ID

Built 1977 Load: 21.8 t ADT: 630

US 95

Fair

Over: PEND OREILLE R;SANDPOINT

1.0 S. SANDPOINT, Bonner, ID

Built 1981 Load: 21.8 t ADT: 18,000

I 84 WB ON RAMP

Fair

Over: I 84 WB OFF RAMP

4.5 W. BOISE, Ada, ID

Built 2003 Load: 21.8 t ADT: 4,500

STC2818;E FORK RD

Fair

Over: BIG WOOD RIVER

6.0 N. 1.6 W. HAILEY, Blaine, ID

Built 1974 Load: 21.8 t ADT: 2,700

STC5722;CHATCOLET

Fair

Over: PLUMMER CREEK

IN CHATCOLET, Benewah, ID

Built 1961 Load: 21.8 t ADT: 360

STC5752;PRICHARD S

Fair

Over: PRICHARD CR;PRICHARD TRS

0.1 N. 0.2 E. PRICHARD, Shoshone, ID

Built 1950 Load: 21.8 t ADT: 450

STC 5803;MOYIE RVR

Fair

Over: MOYIE RIVER;MEADOW CREEK

10.2 S. ADDIE, Boundary, ID

Built 1928 Load: 21.8 t ADT: 120

STC 6712;S 25TH E

Fair

Over: TAYLOR CANAL

4.48 S. AMMON, Bonneville, ID

Built 1949 Load: 21.8 t ADT: 1,600

400 NORTH ROAD

Fair

Over: BLACKFOOT CANAL

0.5 N. 0.2 E. WAPELLO, Bingham, ID

Built 1965 Load: 21.8 t ADT: 200

FUNK ROAD

Fair

Over: LOW LINE CANAL

2.5S. 0.9E.ABERDEEN;2000S, Bingham, ID

Built 1958 Load: 21.8 t ADT: 200

N 2200 W

Fair

Over: WEST CACHE CANAL

2.1 N. 2.8 W. PRESTON, Franklin, ID

Built 1960 Load: 21.8 t ADT: 100

FRONTAGE ROAD

Fair

Over: ROCK CR;REGISTER ROCK BR

9.0S 8.3W AMERICAN FALLS, Power, ID

Built 1981 Load: 21.8 t ADT: 100

990 SOUTH ROAD

Fair

Over: MILNER GOODING CANAL

1.5 S. 5.5 E. HAZELTON, Jerome, ID

Built 1929 Load: 21.8 t ADT: 560

STC 3725;PERCH RD

Fair

Over: MORA CANAL

3.4 S. 7.5 W. NAMPA, Canyon, ID

Built 1982 Load: 21.8 t ADT: 350

DUCK LANE

Fair

Over: MORA CANAL

3.8 S. 4.3 W. NAMPA, Canyon, ID

Built 1983 Load: 21.8 t ADT: 50

STEPHEN LANE

Fair

Over: RIVERSIDE CANAL

3.2 S. 0.7 W. PARMA, Canyon, ID

Built 1983 Load: 21.8 t ADT: 200

STC 3723;ROBINSON

Fair

Over: NEW YORK CANAL

3.3 S. 3.5 E. NAMPA, Canyon, ID

Built 1981 Load: 21.8 t ADT: 2,300

S. 12TH AVENUE

Fair

Over: INDIAN CREEK

IN CALDWELL;S.12TH AVE, Canyon, ID

Built 1935 Load: 21.8 t ADT: 560

WARD ROAD NORTH

Fair

Over: RUSH CREEK

6.4N 0.5W CAMBRIDGE, Washington, ID

Built 2002 Load: 21.8 t ADT: 30

MOSCRIP ROAD

Fair

Over: OROFINO CREEK

IN PIERCE, Clearwater, ID

Built 1978 Load: 21.8 t ADT: 190

FREE USE ROAD

Fair

Over: WHITEBIRD CREEK

1.0 N. 1.0 E. WHITEBIRD, Idaho, ID

Built 1950 Load: 21.8 t ADT: 140

JENKINS ROAD

Fair

Over: COW CREEK

2.5 N. 1.6 E. GENESEE, Latah, ID

Built 1935 Load: 21.8 t ADT: 30

STC4803;OLD HWY 95

Fair

Over: COW CREEK

3.5 N. 0.6 E. GENESEE, Latah, ID

Built 1930 Load: 21.8 t ADT: 120

STC4803;OLD HWY 95

Fair

Over: COW CREEK

4.9 N. 0.4 W. GENESEE, Latah, ID

Built 1930 Load: 21.8 t ADT: 120

HATTER CREEK ROAD

Fair

Over: HATTER CREEK

0.8 S. PRINCETON, Latah, ID

Built 1970 Load: 21.8 t ADT: 30

WHISKEY JACK

Fair

Over: BOYER SLOUGH;SE.KOOTENAI

0.2 S. 1.0 E. KOOTENAI, Bonner, ID

Built 1969 Load: 21.8 t ADT: 130

POIRIRE RANCH RD

Fair

Over: BLANCHARD CREEK

0.8 S. 0.8 W. BLANCHARD, Bonner, ID

Built 1965 Load: 21.8 t ADT: 80

NF-985;HORDS RANCH

Fair

Over: PLACER CREEK

2.5 S. 1.0 E. WALLACE, Shoshone, ID

Built 1960 Load: 21.8 t ADT: 20

TAYLOR ST/LANDBANK

Fair

Over: PORTER CANAL

IN IDAHO FALLS, Bonneville, ID

Built 1965 Load: 21.8 t ADT: 300

E 300 N

Fair

Over: EGIN CANAL

0.6 S. 0.1 E. EGIN, Fremont, ID

Built 1985 Load: 21.8 t ADT: 60

ROBINSON CREEK RD

Fair

Over: ROBINSON CREEK

0.3 S. 3.3 E. WARM RIVER, Fremont, ID

Built 1935 Load: 21.8 t ADT: 30

N 4950 E

Fair

Over: EAGLE ROCK CANAL

0.2 N. 3.1 E. RIRIE, Jefferson, ID

Built 1950 Load: 21.8 t ADT: 550

W 7200 S

Fair

Over: REID CANAL

0.3 N. 1.5 W. ARCHER, Madison, ID

Built 1961 Load: 21.8 t ADT: 150

E FORK ROAD

Fair

Over: STAR HOPE CREEK

14.6 W. MACKAY, Custer, ID

Built 1980 Load: 21.8 t ADT: 25

FRONT AVENUE

Fair

Over: CDA PARKING GARAGE

IN COEUR DALENE, Kootenai, ID

Built 2014 Load: 21.8 t ADT: 6,049

FS ROUTE NO. 447

Fair

Over: E.F. EMERALD

E.F. EMERALD CREEK, Benewah, ID

Built 1967 Load: 22.0 t ADT: 40

FS ROUTE NO. 321

Fair

Over: MARBLE CREEK

MARBLE CREEK, Shoshone, ID

Built 1959 Load: 22.0 t ADT: 50

FDR 1433

Fair

Over: N FK PALOUSE

23 MILES FROM POTLATCH RS, Latah, ID

Built 1963 Load: 22.0 t ADT: 10

SMITH CREEK ROAD

Fair

Over: SMITH CREEK

2.8 MI. NE OF PRAIRIE, Elmore, ID

Built 1972 Load: 22.0 t ADT: 25

WILLIS FLAT ROAD

Fair

Over: SO.FK.PAYETTE RIVER

14 MI EAST OF LOWMAN ID, Boise, ID

Built 1959 Load: 22.0 t ADT: 35

SQ___ CREEK ROAD

Fair

Over: JACKKNIFE CREEK

NO DATA ENTERED, Bonneville, ID

Built 1963 Load: 22.0 t ADT: 20

FDR

Fair

Over: WARM SPRINGS CREEK

16 MILES WEST OF KETCHUM, Blaine, ID

Built 1959 Load: 22.0 t ADT: 50

ROAD

Fair

Over: BIG SPRINGS OUTLET

NO DATA ENTERED, Fremont, ID

Built 1957 Load: 22.0 t ADT: 50

FS ROUTE NO. 411

Fair

Over: BURNT CABIN CR

BURNT CABIN CREEK, Kootenai, ID

Built 1948 Load: 22.4 t ADT: 50

Showing 851-900 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.