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

STC6732;OLD HWY 91

Fair

Over: BEAVER CREEK

5.0 N. 1.0 W. HAMER, Jefferson, ID

Built 1963 Load: 26.3 t ADT: 280

CAMAS CREEK ROAD

Fair

Over: I 15 NB-SB;HAMER IC

AT HAMER, Jefferson, ID

Built 1960 Load: 26.3 t ADT: 1,100

CANYON CREEK RD

Fair

Over: CANYON CREEK

6.5 S. 16.4 E. REXBURG, Madison, ID

Built 1970 Load: 26.3 t ADT: 60

9500 SOUTH

Fair

Over: TRAIL CREEK

1.2 S. 1.0 E. VICTOR, Teton, ID

Built 1952 Load: 26.3 t ADT: 120

INDIAN CREEK RD

Fair

Over: INDIAN CREEK(#2)

22.0 NW SALMON, Lemhi, ID

Built 1970 Load: 26.3 t ADT: 15

FS ROUTE NO. 534

Fair

Over: TRAIL CREEK

TRAIL CREEK, Kootenai, ID

Built 1953 Load: 26.6 t ADT: 50

FS ROUTE NO. 419

Fair

Over: MORRIS CREEK

MORRIS CREEK, Bonner, ID

Built 1952 Load: 26.6 t ADT: 50

FS ROUTE NO. 2517

Fair

Over: SPRUCE CREEK

SPRUCE CREEK, Boundary, ID

Built 1977 Load: 26.6 t ADT: 40

FDR 711

Fair

Over: QUARTZ CREEK NO 2

48 MILES FROM PIERCE ID, Clearwater, ID

Built 1967 Load: 26.6 t ADT: 5

NO DATA ENTERED

Fair

Over: SWAMP CREEK

ELK SUMMIT ROAD 111, Idaho, ID

Built 1950 Load: 26.6 t ADT: 30

FOREST ROAD 309

Fair

Over: MILL CREEK

2.1 MI. FROM STATE HWY 14, Idaho, ID

Built 1966 Load: 26.6 t ADT: 30

FOREST ROAD 309

Fair

Over: MILL CREEK

2.8 MI. FROM STATE HWY 14, Idaho, ID

Built 1966 Load: 26.6 t ADT: 30

CUSTER MOTORWAY

Fair

Over: YANKEE FORK

NO DATA ENTERED, Custer, ID

Built 1969 Load: 26.6 t ADT: 100

BASIN CREEK ROAD

Fair

Over: EAST FORK BASIN CREEK

NO DATA ENTERED, Custer, ID

Built 1979 Load: 26.6 t ADT: 40

BEAR VALLEY CR. RD

Fair

Over: BEAR VALLEY CREEK

BEAR VALLEY CREEK, Lemhi, ID

Built 1966 Load: 26.6 t ADT: 10

FDR

Fair

Over: PARADISE CREEK

BIG SMOKEY ADMIN. SITE, Camas, ID

Built 1962 Load: 26.6 t ADT: 50

NO DATA ENTERED

Fair

Over: BEAVER CREEK

FLUME BRIDGE, Clearwater, ID

Built 1967 Load: 26.9 t ADT: 140

FDR 373

Fair

Over: BRUSHY FORK

22 MI EAST OF POWELL R S, Idaho, ID

Built 1956 Load: 26.9 t ADT: 60

FDR 111

Fair

Over: WHITE SANDS CREEK

WHITE SANDS-RD 111, Idaho, ID

Built 1970 Load: 26.9 t ADT: 50

YUBA RIVER ROAD

Fair

Over: YUBA RIVER

2 MI SW ATLANTA IDAHO, Elmore, ID

Built 1976 Load: 26.9 t ADT: 15

DIGGIE ROAD

Fair

Over: NORTH CANAL

2.1 S. 0.5 W. BLACKFOOT, Bingham, ID

Built 1986 Load: 27.0 t ADT: 150

GOODRICH CREEK RD

Fair

Over: WEISER RIVER

5.4 S. 5.7 W. COUNCIL, Adams, ID

Built 1930 Load: 27.0 t ADT: 140

BISHOP ROAD

Fair

Over: NOBLE CANAL

0.2 N. 1.2 W. LETHA, Gem, ID

Built 1974 Load: 27.0 t ADT: 50

DRY CREEK ROAD

Fair

Over: LITTLE WILLOW CREEK

9.7N 8.5E NEW PLYMOUTH, Payette, ID

Built 1974 Load: 27.0 t ADT: 50

E MILO ROAD

Fair

Over: HARRISON CANAL

4.5 W. RIRIE, Bonneville, ID

Built 1949 Load: 27.0 t ADT: 510

81ST S/COUNTY LINE

Fair

Over: LOWER HOLMES CANAL

4.5 S. 6.2 W. IDAHO FALLS, Bonneville, ID

Built 1965 Load: 27.0 t ADT: 80

SHELTON CEMETRY RD

Fair

Over: ANDERSON CANAL

1.0 S. 1.1 W. RIRIE, Bonneville, ID

Built 1941 Load: 27.0 t ADT: 1,700

S6844;LTL LOST RVR

Fair

Over: LITTLE LOST RIVER

32.3 N. 4.0 W. ARCO, Butte, ID

Built 1979 Load: 27.0 t ADT: 200

N 4600 E

Fair

Over: RUDY CANAL

2.0 N. 0.4 W. RIRIE, Jefferson, ID

Built 1973 Load: 27.0 t ADT: 20

528 NORTH RD

Fair

Over: ISLAND CANAL;LABELLE BR

0.2 E. LABELLE, Jefferson, ID

Built 1973 Load: 27.0 t ADT: 15

SH 8

Fair

Over: W.FK.POTLATCH RIVER

0.1 W. BOVILL, Latah, ID

Built 1958 Load: 27.2 t ADT: 1,000

US 20 WBL & EBL

Fair

Over: BOISE RIVER

IN BOISE;BOISE CONNECTOR, Ada, ID

Built 1990 Load: 27.2 t ADT: 36,500

US 20 WBL

Fair

Over: SH 33;REXBURG IC

0.5 W. REXBURG;SH 33, Madison, ID

Built 1981 Load: 27.2 t ADT: 11,750

US 30

Fair

Over: DEER CROSSING

1.8 E. LAVA HOT SPRINGS, Bannock, ID

Built 1977 Load: 27.2 t ADT: 4,300

US 30

Fair

Over: DEER CROSSING

2.5 E. LAVA HOT SPRINGS, Bannock, ID

Built 1977 Load: 27.2 t ADT: 4,300

SH 33

Fair

Over: TETON ISLAND CANAL

2.0 N. REXBURG, Madison, ID

Built 1939 Load: 27.2 t ADT: 4,000

SH 39

Fair

Over: HEGE DRAIN

5.1 S. ABERDEEN, Bingham, ID

Built 1962 Load: 27.2 t ADT: 2,600

SH 45

Fair

Over: MORA CANAL

7.5 S. NAMPA, Canyon, ID

Built 1956 Load: 27.2 t ADT: 3,400

SH 48

Fair

Over: SNAKE RIVER DRY BED

0.5 N. LEWISVILLE, Jefferson, ID

Built 1980 Load: 27.2 t ADT: 1,800

SH 55

Fair

Over: DEER FLAT CANAL

3.5 W. NAMPA, Canyon, ID

Built 1973 Load: 27.2 t ADT: 19,000

SH 55

Fair

Over: BIG CREEK

4 S. CASCADE, Valley, ID

Built 1933 Load: 27.2 t ADT: 4,200

SH 78

Fair

Over: BIRCH CREEK

24.8 E. MURPHY, Owyhee, ID

Built 1954 Load: 27.2 t ADT: 1,100

I 84 EB OFF RAMP

Fair

Over: BOISE RIVER;RAMP AB BR

IN CALDWELL, Canyon, ID

Built 1980 Load: 27.2 t ADT: 5,000

I 90 EBL & WBL

Fair

Over: S.FK.COEUR DALENE RIVER

3.0 E. WALLACE, Shoshone, ID

Built 1962 Load: 27.2 t ADT: 10,500

I 90RAMP EB ON

Fair

Over: S.FK.CDA R.;EB ON RAMP

3.6 E. WALLACE, Shoshone, ID

Built 1964 Load: 27.2 t ADT: 20

SH 75

Fair

Over: BIG WOOD RIVER

14.6 N. KETCHUM, Blaine, ID

Built 1958 Load: 27.2 t ADT: 1,500

SH 97

Fair

Over: COEUR DALENE RIVER

0.6 N. HARRISON, Kootenai, ID

Built 2007 Load: 27.2 t ADT: 790

S 2200 E

Fair

Over: I 84;EIRR;S 2200 E GS

5.9 W. JEROME, Gooding, ID

Built 1971 Load: 27.2 t ADT: 460

SMA 3824;BANKS LOW

Fair

Over: ROCK CLIFF GINI HALF BRD

0.5 S. 7.3 W. LOWMAN, Boise, ID

Built 1991 Load: 27.2 t ADT: 660

STC3830;IDAHO BLVD

Fair

Over: PAYETTE RIVER;E.LETHA BR

1.0 E. LETHA, Gem, ID

Built 1960 Load: 27.2 t ADT: 1,400

Showing 1,251-1,300 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.