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

NO DATA ENTERED

Fair

Over: YANKEE FORK

NO DATA ENTERED, Custer, ID

Built 1972 Load: 14.9 t ADT: 50

FDR

Fair

Over: WOOD RIVER

13 MILES FROM SNRA HQTS, Blaine, ID

Built 1962 Load: 15.2 t ADT: 50

STC 1775;TURNER RD

Fair

Over: BEAR R.;GRACE-TURNER BR.

0.6 W. GRACE, Caribou, ID

Built 1955 Load: 15.4 t ADT: 350

STC 6876;HAYDEN CR

Fair

Over: HAYDEN CREEK

2 W. 0.8 S. LEMHI, Lemhi, ID

Built 1960 Load: 15.4 t ADT: 160

1400 SOUTH ROAD

Fair

Over: DRY CREEK

4.0 N. 2.7 W. GOODING, Gooding, ID

Built 1930 Load: 15.4 t ADT: 30

TUCKER ROAD

Fair

Over: DIXIE SLOUGH

1.2 N. 3.4 E. WILDER, Canyon, ID

Built 1990 Load: 15.4 t ADT: 20

DAVIS ROAD

Fair

Over: LITTLE VALLEY CREEK

1.6 S. 4.0 W. BRUNEAU, Owyhee, ID

Built 1938 Load: 15.4 t ADT: 50

SE 2ND AVENUE

Fair

Over: LANGLEY GULCH

2.5S 1.2E NEW PLYMOUTH, Payette, ID

Built 1975 Load: 15.4 t ADT: 250

GOLD FORK ROAD

Fair

Over: KENNALLY CREEK

3.0 S. 5.3 E. DONNELLY, Valley, ID

Built 1990 Load: 15.4 t ADT: 80

STC7684;SAND ROAD

Fair

Over: S.FK.PALOUSE RIVER

IN MOSCOW, Latah, ID

Built 1971 Load: 15.4 t ADT: 550

PARADISE CRK ST

Fair

Over: PARADISE CREEK

IN MOSCOW @ U OF I, Latah, ID

Built 1967 Load: 15.4 t ADT: 4,200

TERROR GULCH

Fair

Over: S.FK.CDA R;TERROR GULCH

0.7 N. 1.1 W. OSBURN, Shoshone, ID

Built 1973 Load: 15.4 t ADT: 870

EMERSON ST.

Fair

Over: BUTTE ARM CANAL

IN IDAHO FALLS;EMERSON ST, Bonneville, ID

Built 1956 Load: 15.4 t ADT: 670

COTTOM LANE

Fair

Over: LEMHI RIVER

7.2 S. 7.1 E. LEMHI, Lemhi, ID

Built 1950 Load: 15.4 t ADT: 70

W 6800 S

Fair

Over: LIBERTY PARK CANAL

1.7 S. 0.5 E. THORTON, Madison, ID

Built 2001 Load: 15.4 t ADT: 140

ABSTEIN LANE

Fair

Over: E.FK. OF S.FK.SALMON RVR

IN YELLOW PINE, Valley, ID

Built 1920 Load: 15.4 t ADT: 30

ERICKSON RD

Fair

Over: BENEWAH CREEK

3.7 N. 3.1 E. BENEWAH, Benewah, ID

Built 1970 Load: 15.4 t ADT: 50

FOREST ROAD 233

Fair

Over: E. FK. CROOKED RIVER

NO DATA ENTERED, Idaho, ID

Built 2004 Load: 15.6 t ADT: 50

SIXBIT ROAD

Fair

Over: S. FK SALMON RIVER

5 MI N. OF WARM LAKE, Valley, ID

Built 1976 Load: 15.6 t ADT: 15

SIX ML.-RD.VALLEY

Fair

Over: MIDDLE FK PAYETTE RIVER

17 MI N. OF CROUCH ID, Valley, ID

Built 1975 Load: 15.6 t ADT: 20

FDR 581

Fair

Over: KELLY CREEK

OLD KELLY RANGER STATION, Clearwater, ID

Built 1940 Load: 15.9 t ADT: 30

FDR 255

Fair

Over: MOOSE CREEK

MOOSE & KELLY CR JCT, Clearwater, ID

Built 1949 Load: 15.9 t ADT: 40

CAMPGROUND ROAD

Fair

Over: CUB RIVER

NO DATA ENTERED, Franklin, ID

Built 1964 Load: 15.9 t ADT: 30

1700 EAST ROAD

Fair

Over: C CANAL

3.3 S. 1.0 E. EDEN, Jerome, ID

Built 1972 Load: 16.2 t ADT: 200

FS ROUTE NO. 509

Fair

Over: BLUFF CREEK

BLUFF CREEK, Shoshone, ID

Built 1993 Load: 16.2 t ADT: 50

FDR

Fair

Over: PARIDISE CREEK

BIG SMOKY JCT, Camas, ID

Built 1977 Load: 16.2 t ADT: 50

STC2713;3700 N. RD

Fair

Over: LOW LINE CANAL

2S/2.5E FILER;3700N-2450E, Twin Falls, ID

Built 1953 Load: 16.3 t ADT: 1,900

STC2739;3800 E. RD

Fair

Over: ROCK CREEK

6 S. HANSEN;3075N-3800E, Twin Falls, ID

Built 1965 Load: 16.3 t ADT: 990

SMA7522;400 S. RD.

Fair

Over: B-4 CANAL;EMERSON BR

3.0 S. 0.7 W. PAUL, Minidoka, ID

Built 1956 Load: 16.3 t ADT: 3,700

STP 8213;MIDDLETON

Fair

Over: CALDWELL HIGHLINE CANAL

4.0 S. 0.3 E. MIDDLETON, Canyon, ID

Built 1950 Load: 16.3 t ADT: 9,400

S3890;W INDIAN VLY

Fair

Over: GRAYS CREEK

2.7N. 2.4W. INDIAN VALLEY, Adams, ID

Built 1935 Load: 16.3 t ADT: 160

STC 5805;WESTSIDE

Fair

Over: LONG CANYON CREEK

3.2 S. 1.8 W. PORTHILL, Boundary, ID

Built 1956 Load: 16.3 t ADT: 70

STC6705;ST CLAIR

Fair

Over: W. BRANCH SAND CREEK

3.8 S. 1.9 E. IDAHO FALLS, Bonneville, ID

Built 1966 Load: 16.3 t ADT: 2,600

STC7456; E IONA RD

Fair

Over: SAND CREEK

2.0 W. IONA, Bonneville, ID

Built 1957 Load: 16.3 t ADT: 4,300

STC6724;65TH SOUTH

Fair

Over: GREAT WESTERN CANAL

3.6 S. 5.7 W.IDAHO FALLS, Bonneville, ID

Built 1951 Load: 16.3 t ADT: 110

STC 6725; N55TH E

Fair

Over: SAND CREEK

2.5 N. IONA, Bonneville, ID

Built 1953 Load: 16.3 t ADT: 1,300

STC 6748(N 3950 E)

Fair

Over: LEWISVILLE CANAL

1.0 N. RIGBY, Jefferson, ID

Built 1950 Load: 16.3 t ADT: 1,900

E 1000 N

Fair

Over: CONANT CREEK

1.8 N. 3.8 W. DRUMMOND, Fremont, ID

Built 1954 Load: 16.3 t ADT: 100

STC 6851; S 1ST E

Fair

Over: SAND CREEK

1.5 N. TAYLORVILLE, Bonneville, ID

Built 1962 Load: 16.3 t ADT: 970

SMA 7923;LINDEN RD

Fair

Over: NOTUS CANAL

IN CALDWELL;E.LINDEN RD, Canyon, ID

Built 1968 Load: 16.3 t ADT: 8,200

SMA 8233;MIDLAND B

Fair

Over: PHYLLIS CANAL

N NAMPA;MIDLAND BLVD., Canyon, ID

Built 1973 Load: 16.3 t ADT: 8,000

THOMAS FORK LANE

Fair

Over: THOMAS FK.CR;SE.GENEVA B

1.0 S. 0.3 E. GENEVA, Bear Lake, ID

Built 1986 Load: 16.3 t ADT: 30

N 550 E;IDAHO ROAD

Fair

Over: BLACKFOOT CANAL

0.8 S. 0.2 W. FIRTH, Bingham, ID

Built 1962 Load: 16.3 t ADT: 300

COUNTRY CLUB;1400N

Fair

Over: LITTLE SAND CREEK

1.0 N. 3.5 E. SHELLEY, Bingham, ID

Built 1959 Load: 16.3 t ADT: 160

S. FIRTH ROAD

Fair

Over: RESERVATION CANAL

0.6 S. 0.3 E. FIRTH, Bingham, ID

Built 1967 Load: 16.3 t ADT: 220

ARMY WAY

Fair

Over: ABERDEEN SPRINGFIELD CNL

1.0 N. 3.7 W. RIVERSIDE, Bingham, ID

Built 1963 Load: 16.3 t ADT: 100

N 800 W; PERKS RD

Fair

Over: PEOPLES CANAL

1.1 N. 0.6 W. MORELAND, Bingham, ID

Built 1966 Load: 16.3 t ADT: 95

STC 1841;1950 W

Fair

Over: ABERDEEN SPRINGFIELD CNL

1.5 N. SPRINGFIELD, Bingham, ID

Built 1969 Load: 16.3 t ADT: 220

1700 SOUTH ROAD

Fair

Over: HIGH LINE CANAL

0.5 N. 2.0 W.ABERDEEN, Bingham, ID

Built 1962 Load: 16.3 t ADT: 200

UNDERWOOD ROAD

Fair

Over: HIGH LINE CANAL

5.3 N. 0.5 E. ABERDEEN, Bingham, ID

Built 1980 Load: 16.3 t ADT: 100

Showing 151-200 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.