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

FS ROUTE NO. 447

Fair

Over: EMERALD CREEK

EMERALD CREEK, Benewah, ID

Built 1967 Load: 22.4 t ADT: 50

FOREST ROAD 1858

Fair

Over: NEWSOME CREEK

NEWSOME DRAINAGE, Idaho, ID

Built 1962 Load: 22.4 t ADT: 50

FOREST ROAD 1858

Fair

Over: NEWSOME CREEK

NEWSOME DRAINAGE, Idaho, ID

Built 1961 Load: 22.4 t ADT: 50

SMITH CREEK ROAD

Fair

Over: SMITH CREEK

5.7 MI. NE OF PRAIRIE, Elmore, ID

Built 1972 Load: 22.4 t ADT: 25

BARBER FLAT ROAD

Fair

Over: NORTH FORK BOISE RIVER

25 MI EAST OF ID CITY, Elmore, ID

Built 1959 Load: 22.4 t ADT: 15

NO DATA ENTERED

Fair

Over: HAZARD CREEK

NO DATA ENTERED, Idaho, ID

Built 1951 Load: 22.4 t ADT: 50

NO DATA ENTERED

Fair

Over: PANTHER CREEK

5.2 MILES SW OF COBALT, Lemhi, ID

Built 1953 Load: 22.4 t ADT: 50

FDR

Fair

Over: BIG SMOKY CREEK

2 MILES WEST BIG SMOKY JT, Camas, ID

Built 1953 Load: 22.4 t ADT: 50

STC 5786;COLBURN

Fair

Over: PACK RIVER

10.3 NE. SANDPOINT, Bonner, ID

Built 1951 Load: 22.5 t ADT: 1,300

SAND CREEK RD;900N

Fair

Over: E.BR.SNAKE R.VALLEY CNL

4.0 S. 1.1E. SHELLEY, Bingham, ID

Built 1968 Load: 22.5 t ADT: 100

2000 EAST ROAD

Fair

Over: LOW LINE CANAL

1.0S 2.0W FILER;JRDN COR, Twin Falls, ID

Built 1965 Load: 22.5 t ADT: 330

CRABB ROAD

Fair

Over: HANGMAN CREEK

2.0 N. 4.2 W. TENSED, Benewah, ID

Built 1981 Load: 22.5 t ADT: 30

STC 6709;N 4200 E

Fair

Over: LONG ISLAND CANAL

0.7 S. 0.2 W. LABELLE, Jefferson, ID

Built 1969 Load: 22.5 t ADT: 160

SH 3

Fair

Over: BIG BEAR CREEK

AT KENDRICK NCL, Latah, ID

Built 1954 Load: 22.7 t ADT: 2,500

US 12

Fair

Over: WAWAALAMNIME CREEK

20.6 W. IDA-MONT LINE, Idaho, ID

Built 1960 Load: 22.7 t ADT: 530

SH 21

Fair

Over: CROOKED CREEK

3.1 W. STANLEY, Custer, ID

Built 1968 Load: 22.7 t ADT: 1,800

SH 25

Fair

Over: L CANAL

7.0 E. JEROME, Jerome, ID

Built 1933 Load: 22.7 t ADT: 1,100

SH 34

Fair

Over: TINCUP CREEK

17 E. WAYAN, Caribou, ID

Built 1962 Load: 22.7 t ADT: 540

SH 75

Fair

Over: FOURTH OF JULY CREEK

3.8 S. OBSIDIAN, Custer, ID

Built 1974 Load: 22.7 t ADT: 750

SMA 3824;BNKS LWMN

Fair

Over: DEADWOOD RIVER

22.1 E. CROUCH, Boise, ID

Built 1985 Load: 22.7 t ADT: 660

STC3892;INDIAN VLY

Fair

Over: GRAYS CREEK

1.9N. 0.5W. INDIAN VALLEY, Adams, ID

Built 1930 Load: 22.7 t ADT: 160

OLD RIVER ROAD

Fair

Over: ST JOE RIVER;AVERY BR

IN AVERY, Shoshone, ID

Built 1935 Load: 22.7 t ADT: 320

STC 6719;E 113 N

Fair

Over: ANDERSON CANAL

0.2 N. 3.9 E. UCON, Bonneville, ID

Built 1949 Load: 22.7 t ADT: 450

STC 6731;55TH EAST

Fair

Over: HARRISON CANAL

2.3 N. 2 E. UCON, Jefferson, ID

Built 1961 Load: 22.7 t ADT: 3,900

STP7343;ORCHARD ST

Fair

Over: I 184B;ORCHARD ST GS

IN BOISE;ORCHARD ST., Ada, ID

Built 1968 Load: 22.7 t ADT: 18,500

STP 7391;S. MAIN

Fair

Over: PORTNEUF RIVER

2.0 S. POCATELLO, Bannock, ID

Built 1967 Load: 22.7 t ADT: 7,800

SMA 7406;PANCHERI

Fair

Over: SNAKE RIVER

IN IDAHO FALLS, Bonneville, ID

Built 1971 Load: 22.7 t ADT: 24,500

CHICAGO ST.

Fair

Over: BOISE RIVER

IN CALDWELL, Canyon, ID

Built 1980 Load: 22.7 t ADT: 1,000

COUNTY ROAD

Fair

Over: BEAR RIVER

0.8 N. 1.7 W. BENNINGTON, Bear Lake, ID

Built 1984 Load: 22.7 t ADT: 70

EXPERIMENT ROAD

Fair

Over: LOW LINE CANAL

3.2S. 0.5E.ABERDEEN;2700W, Bingham, ID

Built 1958 Load: 22.7 t ADT: 200

COUNTY ROAD

Fair

Over: I 15;MACHINE PASS GS

14.0 N. POCATELLO, Bingham, ID

Built 1960 Load: 22.7 t ADT: 50

E SUGAR CREEK ROAD

Fair

Over: CUB CREEK

0.1 E. MAPLETON, Franklin, ID

Built 2001 Load: 22.7 t ADT: 20

RAINBOW ROAD

Fair

Over: I 86 EB-WB;RAINBOW RD GS

10.6 E. AMERICAN FALLS, Power, ID

Built 1972 Load: 22.7 t ADT: 200

EAST FORK ROAD

Fair

Over: HYNDMAN CREEK

0.6 E. TRIUMPH, Blaine, ID

Built 1994 Load: 22.7 t ADT: 700

CLOVER CREEK RD

Fair

Over: I 84;CLOVER CREEK RD GS

0.6 E. BLISS, Gooding, ID

Built 1975 Load: 22.7 t ADT: 400

STC 3771;KING ROAD

Fair

Over: MORA CANAL

1.2 S. 4.0 E. KUNA, Ada, ID

Built 1978 Load: 22.7 t ADT: 600

PINES ROAD

Fair

Over: LITTLE SALMON RIVER

0.6 N. 0.3 W. PINEHURST, Adams, ID

Built 1925 Load: 22.7 t ADT: 50

BEET ROAD

Fair

Over: LOW LINE CANAL

7.0 S. 0.3 E. NOTUS, Canyon, ID

Built 1992 Load: 22.7 t ADT: 100

STC4705;DOUMECQ RD

Fair

Over: SALMON R;WHITEBIRD TRUSS

1.3 S. 1.2 W. WHITEBIRD, Idaho, ID

Built 1935 Load: 22.7 t ADT: 390

KUBE ROAD

Fair

Over: SHEBANG CREEK

7.6 N. 4.7 W. GRANGEVILLE, Idaho, ID

Built 1965 Load: 22.7 t ADT: 20

S. TAMARACK ST

Fair

Over: COW CREEK

0.2 S. GENESEE, Latah, ID

Built 1935 Load: 22.7 t ADT: 50

ROCK CREEK ROAD

Fair

Over: PALOUSE R;SE.POTLATCH BR

0.4 S. 0.1 E. POTLATCH, Latah, ID

Built 1965 Load: 22.7 t ADT: 550

YUKON ROAD

Fair

Over: MISSION CREEK;KELLOGG BR

1.7 N. 2.5 E. COPELAND, Boundary, ID

Built 1978 Load: 22.7 t ADT: 30

E BLUE LAKE RD

Fair

Over: THOMPSON LAKE OUTLET BR

2.2 N. 2.7 E. HARRISON, Kootenai, ID

Built 1986 Load: 22.7 t ADT: 100

3400 NORTH ROAD

Fair

Over: MOORE CANAL

2.3 N. 0.2 E. MOORE, Butte, ID

Built 1979 Load: 22.7 t ADT: 80

S YELLOWSTONE HWY

Fair

Over: TEXAS SLOUGH

AT THORNTON, Madison, ID

Built 1938 Load: 22.7 t ADT: 120

INDIAN CREEK RD

Fair

Over: INDIAN CREEK(#4)

22.0 NW SALMON, Lemhi, ID

Built 1970 Load: 22.7 t ADT: 15

3209: NORTH PAGARI

Fair

Over: Little Wood River

0.7 mi SE of US26, Lincoln, ID

Built 1980 Load: 22.7 t ADT: 25

FS ROUTE NO. 300A

Fair

Over: SQ___ CREEK

3.7 MILES FROM AVERY ID, Shoshone, ID

Built 1938 Load: 22.7 t ADT: 50

FS ROUTE NO. 628

Fair

Over: BOULDER CREEK

BOULDER CREEK, Boundary, ID

Built 1981 Load: 22.7 t ADT: 50

Showing 901-950 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.