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

CEDAR ROAD

Fair

Over: COTTONWOOD CREEK

0.7 S. 1.2 E. MYRTLE, Nez Perce, ID

Built 1929 Load: 8.2 t ADT: 20

N 45TH E

Fair

Over: NORTH FORK WILLOW CR

1.6 S. 1.0 E. UCON, Bonneville, ID

Built 1958 Load: 8.2 t ADT: 2,000

NO DATA ENTERED

Fair

Over: YANKEE FORK

NO DATA ENTERED, Custer, ID

Built 1972 Load: 8.4 t ADT: 50

FS ROUTE NO. 208

Fair

Over: CDA RIVER

2.5 MI FROM SHOSHONE W.C., Shoshone, ID

Built 1952 Load: 8.7 t ADT: 50

MULDOON CANYON RD

Fair

Over: LITTLE WOOD RIVER

2.7 N. 10.4 E. BELLEVUE, Blaine, ID

Built 1935 Load: 9.1 t ADT: 80

650 WEST ROAD

Fair

Over: MILNER GOODING CANAL

6.9 N. 6.4 W. SHOSHONE, Lincoln, ID

Built 1955 Load: 9.1 t ADT: 110

LEWIS LANE

Fair

Over: NEW YORK CANAL

4.2 S. 1.1 E. NAMPA, Canyon, ID

Built 1984 Load: 9.1 t ADT: 2,000

SAND ROAD

Fair

Over: S.FK.PALOUSE RIVER

1.3 S. 1.1 W. MOSCOW, Latah, ID

Built 1955 Load: 9.1 t ADT: 550

LITTLE CANYON ROAD

Fair

Over: BIG CANYON CREEK

0.4 S. 0.3 E. PECK, Nez Perce, ID

Built 1930 Load: 9.1 t ADT: 190

N 1700 E (S TETON)

Fair

Over: TETON ISLAND CANAL

2.5 N. 2.2 E. REXBURG, Madison, ID

Built 1964 Load: 9.1 t ADT: 60

I 90

Fair

Over: I 90B;CANYON CR

IN WALLACE, Shoshone, ID

Built 1991 Load: 10.0 t ADT: 11,000

3100 NORTH ROAD

Fair

Over: COTTONWOOD CREEK

6.0 S. 0.8 W. KIMBERLY, Twin Falls, ID

Built 1977 Load: 10.0 t ADT: 100

ROCK CREEK ROAD

Fair

Over: ROCK CREEK

13.0 N. 8.7 W. WEISER, Washington, ID

Built 1970 Load: 10.0 t ADT: 5

KUBE ROAD

Fair

Over: STOCK CREEK

8.5 N. 4.5 W. GRANGEVILLE, Idaho, ID

Built 1965 Load: 10.0 t ADT: 80

LONGHAUL ROAD

Fair

Over: LONGHAUL CREEK

4.6 N. GRANGEVILLE, Idaho, ID

Built 1960 Load: 10.0 t ADT: 60

CAPITOL AVENUE

Fair

Over: SWAUGER SLOUGH

IN MACKAY, Custer, ID

Built 1940 Load: 10.0 t ADT: 1,220

CARMEN CREEK ROAD

Fair

Over: CARMEN CREEK

NO DATA ENTERED, Lemhi, ID

Built 1961 Load: 10.0 t ADT: 10

2407: WENDELL SHEE

Fair

Over: Twin Falls N. Side Canal

7.2 mi E of ID46, Jerome, ID

Built 1984 Load: 10.4 t ADT: 25

FDR 105

Fair

Over: NF CLEARWATER RIVER

WEITAS CREEK & NF CLW RIV, Clearwater, ID

Built 1937 Load: 10.7 t ADT: 20

SH 6

Fair

Over: PALOUSE RIVER;HARVARD BR

1.5 N. HARVARD, Latah, ID

Built 1974 Load: 10.9 t ADT: 710

SMA7334;GUN CLB RD

Fair

Over: LINDSAY CREEK

IN LEWISTON;GUN CLUB RD., Nez Perce, ID

Built 1971 Load: 10.9 t ADT: 5,300

MINGO ROAD

Fair

Over: BENCH CANAL

0.2 N. 0.2 E. GRACE, Caribou, ID

Built 2012 Load: 10.9 t ADT: 30

STC 8317;DUFF LANE

Fair

Over: MILL SLOUGH

0.3 N. 1.3 E. MIDDLETON, Canyon, ID

Built 1957 Load: 10.9 t ADT: 2,300

OLD HIGHWAY 95

Fair

Over: SLATE CREEK

0.2 N. SLATE CREEK R.STA, Idaho, ID

Built 1920 Load: 10.9 t ADT: 50

LONGHAUL ROAD

Fair

Over: LONGHAUL CREEK

4.0 N. GRANGEVILLE, Idaho, ID

Built 1965 Load: 10.9 t ADT: 60

ELK CREEK ROAD

Fair

Over: MOON GULCH;NE.KELLOGG BR

0.1 N. 3.0 E. KELLOGG, Shoshone, ID

Built 1919 Load: 10.9 t ADT: 50

LEMHI ROAD

Fair

Over: LEMHI RIVER(HIGH BR)

2.0 S. 0.5 E. TENDOY, Lemhi, ID

Built 1992 Load: 10.9 t ADT: 50

NO DATA ENTERED

Fair

Over: YANKEE FORK

NO DATA ENTERED, Custer, ID

Built 1972 Load: 11.3 t ADT: 50

2150 N

Fair

Over: BIG LOST RIVER

3.5 S. 0.9 E. ARCO, Butte, ID

Built 1930 Load: 11.7 t ADT: 30

STC5703;SANDERS RD

Fair

Over: SMITH CREEK

1.2 W. SANDERS, Benewah, ID

Built 1947 Load: 11.8 t ADT: 270

STC 5804;LIONS DEN

Fair

Over: DEEP CREEK (MORAVIA BR)

3.5S. 3.7W. BONNERS FERRY, Boundary, ID

Built 1976 Load: 11.8 t ADT: 300

ONEIDA NARROWS RD

Fair

Over: BEAR RIVER (REDPOINT BR)

9.2 N. 5.5 E. PRESTON, Franklin, ID

Built 1980 Load: 11.8 t ADT: 50

2800 EAST ROAD

Fair

Over: LOW LINE CANAL

3.0 S. 1.5 W. TWIN FALLS, Twin Falls, ID

Built 1980 Load: 11.8 t ADT: 140

WILDHORSE ROAD

Fair

Over: WILDHORSE RIVER

11.6 S. 7.2 W. BEAR, Adams, ID

Built 1975 Load: 11.8 t ADT: 30

S. DEWEY AVE

Fair

Over: MILL SLOUGH

AT MIDDLETON SCL, Canyon, ID

Built 1980 Load: 11.8 t ADT: 440

FROMELT ROAD

Fair

Over: OROFINO CREEK

IN PEIRCE, Clearwater, ID

Built 2000 Load: 11.8 t ADT: 190

STC 4751;CTTNWD CR

Fair

Over: COYOTE CREEK

3.1 S. 3.0 E. MYRTLE, Nez Perce, ID

Built 1938 Load: 11.8 t ADT: 40

STC 4751;3RD ST.

Fair

Over: LAPWAI CREEK

AT CULDESAC WCL;3RD ST., Nez Perce, ID

Built 1983 Load: 11.8 t ADT: 240

OLD HWY 91

Fair

Over: PLEASANT VALLEY CREEK

6.9 N. 1.5 W. SPENCER, Clark, ID

Built 1934 Load: 11.8 t ADT: 50

MABEY LANE

Fair

Over: LEMHI RIVER

1.0 S. 0.1 E. TENDOY, Lemhi, ID

Built 1968 Load: 11.8 t ADT: 50

NO DATA ENTERED

Fair

Over: BIG CREEK

BIG CREEK, Shoshone, ID

Built 1939 Load: 12.0 t ADT: 50

FS ROUTE #231

Fair

Over: PACK RIVER

20 MILES FROM SAMUEL ID, Boundary, ID

Built 1988 Load: 12.0 t ADT: 50

RIVER ROAD

Fair

Over: GRAND VIEW IRRG.DIST.CNL

1.0 N. 2.1 W. GRAND VIEW, Owyhee, ID

Built 1986 Load: 12.6 t ADT: 90

FS ROUTE 3099

Fair

Over: CDA RIVER

15.5 MI F/MAGEE R.S., Shoshone, ID

Built 1954 Load: 12.6 t ADT: 50

FOREST ROAD 443

Fair

Over: SELWAY RIVER

SELWAY FALLS, Idaho, ID

Built 1934 Load: 12.6 t ADT: 50

SH 14

Fair

Over: SILVER CREEK

6.6 W. GOLDEN, Idaho, ID

Built 1983 Load: 12.7 t ADT: 150

SMA 7711; ROSE RD

Fair

Over: SNAKE R.;PORTERVILLE BR.

3.0 N. BLACKFOOT, Bingham, ID

Built 1970 Load: 12.7 t ADT: 3,900

STC5703;SANDERS RD

Fair

Over: HANGMAN CREEK

0.5 W. SANDERS, Benewah, ID

Built 1947 Load: 12.7 t ADT: 270

STC 6774;E 2000 N

Fair

Over: S.FK.TETON RIVER

1.2 S. 1 E. SUGAR CITY, Madison, ID

Built 1959 Load: 12.7 t ADT: 1,600

KING LANE

Fair

Over: WARM SPRING CREEK

2.0 S. 1.4 W. ROCKLAND, Power, ID

Built 1965 Load: 12.7 t ADT: 80

Showing 51-100 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.