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

FROST ROAD

Good

Over: LOW LINE CANAL

5.2 S. 5.5 E. WILDER, Canyon, ID

Built 1990 Load: 27.9 t ADT: 50

4002: HUNTER-TRAPP

Good

Over: East Fork Pine Creek

5.6 mi S of I90, Shoshone, ID

Built 1998 Load: 27.9 t ADT: 25

FS ROUTE NO. 2549

Good

Over: SKIN CREEK

SKIN CREEK, Boundary, ID

Built 1957 Load: 27.9 t ADT: 40

NO DATA ENTERED

Good

Over: N F CLEARWATER RIVE

AQUARIOUS BRIDGE, Clearwater, ID

Built 1965 Load: 27.9 t ADT: 145

NO DATA ENTERED

Good

Over: GOOSE CREEK

NO DATA ENTERED, Adams, ID

Built 1963 Load: 27.9 t ADT: 50

NO DATA ENTERED

Good

Over: SILVER CREEK

26 MILES NNW OF CHALLIS, Lemhi, ID

Built 1994 Load: 27.9 t ADT: 5

HAYDEN CR. ROAD

Good

Over: HAYDEN CREEK

NO DATA ENTERED, Lemhi, ID

Built 1974 Load: 27.9 t ADT: 10

SH 55

Good

Over: BOISE RIVER;S.CHANNEL

1.4 S. EAGLE, Ada, ID

Built 1978 Load: 28.1 t ADT: 42,500

STC 1851; E CENTER

Good

Over: W.BR.SNAKE R.VALLEY CNL

IN SHELLEY, Bingham, ID

Built 1966 Load: 28.1 t ADT: 1,700

STC 1863;W 1400 S

Good

Over: HIGH LINE CANAL

3.5 N. 1.3 W. ABERDEEN, Bingham, ID

Built 1968 Load: 28.1 t ADT: 300

STC 4792;CHESTNUT

Good

Over: COW CREEK

IN GENESEE;CHESTNUT ST., Latah, ID

Built 1977 Load: 28.1 t ADT: 210

STC 6711;N 35TH W

Good

Over: GREAT WESTERN CANAL

1.5 N. 3.2 W. IDAHO FALLS, Bonneville, ID

Built 1979 Load: 28.1 t ADT: 1,000

STC 6760;E 400 N

Good

Over: EGIN CANAL

0.4 N. 0.9 E. EGIN, Fremont, ID

Built 1992 Load: 28.1 t ADT: 410

STP 7446;SUNNYSIDE

Good

Over: SAND CREEK

1.1 W. AMMON;SUNNYSIDE, Bonneville, ID

Built 2002 Load: 28.1 t ADT: 28,000

6TH STREET NORTH

Good

Over: PHYLLIS CANAL

IN NAMPA, Canyon, ID

Built 2000 Load: 28.1 t ADT: 5,200

250E;S LAVASIDE RD

Good

Over: NEW LAVASIDE CANAL

6.3 N. 4.8 E. BLACKFOOT, Bingham, ID

Built 1969 Load: 28.1 t ADT: 50

PARK RD; S 5TH W

Good

Over: SAND CREEK

0.8 N. 4.0 E. SHELLEY, Bingham, ID

Built 1970 Load: 28.1 t ADT: 930

FIRTH ROAD

Good

Over: BLACKFOOT CANAL

0.3 N. 0.3 E. FIRTH, Bingham, ID

Built 1970 Load: 28.1 t ADT: 220

SAMBO ROAD

Good

Over: NORTH CANAL

2.8 S. 1.2 W. BLACKFOOT, Bingham, ID

Built 1984 Load: 28.1 t ADT: 160

HANCOCK RD; 100 E

Good

Over: CORBETT SLOUGH CANAL

0.3 N. 1.0 W. WAPELLO, Bingham, ID

Built 1965 Load: 28.1 t ADT: 200

BUTTE RD; N 1000 E

Good

Over: E.BR.SNAKE R.VALLEY CNL

1.6 N. 1.0 W. GOSHEN, Bingham, ID

Built 1974 Load: 28.1 t ADT: 100

BOND ROAD

Good

Over: DANSKIN CANAL

1.2 W. GROVELAND, Bingham, ID

Built 1968 Load: 28.1 t ADT: 1,100

W 150 N; CLARK RD

Good

Over: DANSKIN CANAL

0.3 S. 1.4 E. MORELAND, Bingham, ID

Built 1968 Load: 28.1 t ADT: 1,400

NIEBAUR ROAD

Good

Over: SUNBEAM CREEK

1.4N 3.3E AMERICAN FALLS, Power, ID

Built 1940 Load: 28.1 t ADT: 80

STODDARD ROAD

Good

Over: RIDENBAUGH CANAL

2.2 S. 0.6 W. MERIDIAN, Ada, ID

Built 1968 Load: 28.1 t ADT: 3,900

SMA9613;MCMILLAN R

Good

Over: SETTLERS CANAL

IN BOISE, Ada, ID

Built 2000 Load: 28.1 t ADT: 7,100

STC 7673;GOWEN RD

Good

Over: FIVE MILE CREEK

IN BOISE;GOWEN ROAD, Ada, ID

Built 1940 Load: 28.1 t ADT: 3,000

STP7851;MCDERMOTT

Good

Over: FIVE MILE CREEK

2.3 N. 4.1 W. MERIDIAN, Ada, ID

Built 1991 Load: 28.1 t ADT: 700

STC 9503;GEKELER

Good

Over: RIDENBAUGH CANAL

IN BOISE;GEKELER LANE, Ada, ID

Built 1979 Load: 28.1 t ADT: 4,100

STC 3767;MUNGER RD

Good

Over: MIDDLETON CANAL

1.1 N. 0.6 W. STAR, Ada, ID

Built 1965 Load: 28.1 t ADT: 4,800

SMA3773;LINDER RD

Good

Over: MASON CREEK FEEDER CANAL

3.4 N. 0.3 E. KUNA, Ada, ID

Built 1992 Load: 28.1 t ADT: 4,600

SMA7288;HILLRDPKWY

Good

Over: DRAINAGE DISTRICT NO. 2

IN BOISE, Ada, ID

Built 2001 Load: 28.1 t ADT: 6,700

STC 3717;USTICK RD

Good

Over: LOWLINE CANAL

3.0 S. 5.0 E. WILDER, Canyon, ID

Built 1995 Load: 28.1 t ADT: 2,000

STC 3747;LAKESHORE

Good

Over: NEW YORK CANAL

4.7S 0.9W NAMPA CITY CTR, Canyon, ID

Built 1986 Load: 28.1 t ADT: 3,600

14TH AVE

Good

Over: NOTUS CANAL

CALDWELL, Canyon, ID

Built 1980 Load: 28.1 t ADT: 20

SUGAR AVENUE

Good

Over: INDIAN CREEK

IN NAMPA, Canyon, ID

Built 2004 Load: 28.1 t ADT: 190

STC3702;CLOVER-3CR

Good

Over: E. FORK BRUNEAU RIVER

25.8 W 5.0 S. CASTLEFORD, Owyhee, ID

Built 2000 Load: 28.1 t ADT: 100

ROWLAND ROAD

Good

Over: SHEEP CREEK

12.0 S. 7.3 E. GRASMERE, Owyhee, ID

Built 1995 Load: 28.1 t ADT: 10

HARMONY HEIGHTS RD

Good

Over: OROFINO CREEK(NOAHS BR)

0.1 N. 0.3 E. OROFINO, Clearwater, ID

Built 2000 Load: 28.1 t ADT: 610

DEPT OF LANDS ROAD

Good

Over: ELK CREEK

0.6 N. 0.2 W. ELK RIVER, Clearwater, ID

Built 1982 Load: 28.1 t ADT: 260

HILL STREET

Good

Over: LAWYER CREEK

IN KAMIAH;HILL ST., Idaho, ID

Built 1972 Load: 28.1 t ADT: 1,000

RAPID RIVER ROAD

Good

Over: RAPID RIVER

3.0 S. 1.6 W. RIGGINS, Idaho, ID

Built 1978 Load: 28.1 t ADT: 250

PARK ROAD; NF-1963

Good

Over: HOG MEADOW CREEK

1.6 S. 0.6 E. HELMER, Latah, ID

Built 1973 Load: 28.1 t ADT: 70

OLD RIVER ROAD

Good

Over: MEADOW CREEK

2.4 N. 2.8 E. HARVARD, Latah, ID

Built 1993 Load: 28.1 t ADT: 30

MILL ROAD

Good

Over: S. FK. PALOUSE RIVER

0.7 N. 2.8 E. MOSCOW, Latah, ID

Built 1996 Load: 28.1 t ADT: 80

EISENHOWER STREET

Good

Over: PARADISE CREEK

IN MOSCOW;N.OF D ST., Latah, ID

Built 1975 Load: 28.1 t ADT: 400

W. 7TH STREET

Good

Over: LITTLE BEAR CREEK

IN TROY, Latah, ID

Built 1997 Load: 28.1 t ADT: 50

WESTLAKE ROAD

Good

Over: WILLOW CREEK

1.8 S. 6.0 W. FERDINAND, Idaho, ID

Built 1996 Load: 28.1 t ADT: 70

81ST SOUTH ROAD

Good

Over: TAYLOR CANAL

4.6 S. 2.8 E. IDAHO FALLS, Bonneville, ID

Built 1970 Load: 28.1 t ADT: 150

N 115 E

Good

Over: WILLOW CREEK

1.8 S. 1.4 W. RIRIE, Bonneville, ID

Built 1962 Load: 28.1 t ADT: 50

Showing 3,251-3,300 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.