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. 537

Poor

Over: BIG CREEK

BIG CREEK, Shoshone, ID

Built 1939 Load: 13.6 t ADT: 50

FOREST ROAD 2038

Poor

Over: SLATE CREEK

NO DATA ENTERED, Idaho, ID

Built 1953 Load: 14.3 t ADT: 50

550 EAST ROAD

Poor

Over: MILNER GOODING CANAL

1.8 S. 1.5 W. DIETRICH, Lincoln, ID

Built 1940 Load: 14.5 t ADT: 50

DIVERSION ROAD

Poor

Over: CAMAS CREEK

10.7 S. 1.2 W. KILGORE, Clark, ID

Built 1953 Load: 14.5 t ADT: 50

FUN FARM ROAD

Poor

Over: HENRYS FK SNAKE RIVER

0.9 S. 2.5 W. CHESTER, Fremont, ID

Built 1925 Load: 14.5 t ADT: 30

OLD MIL. RR GRADE

Poor

Over: SLOUGH BRIDGE

1.4N 3.1W CALDER, Shoshone, ID

Built 1912 Load: 14.5 t ADT: 15

FS ROUTE N0. 413

Poor

Over: N.F. CDA RIVER

BREAKWATER, Kootenai, ID

Built 1950 Load: 14.6 t ADT: 50

FOREST ROAD 357

Poor

Over: RUNNING CR

NO DATA ENTERED, Idaho, ID

Built 1956 Load: 14.6 t ADT: 50

FOREST ROAD 421

Poor

Over: LITTLE MALLARD CREEK

AT SALMON RIVER, Idaho, ID

Built 1984 Load: 14.6 t ADT: 50

2421: ASTORQUIA RO

Poor

Over: Twin Falls N. Side Canal

5.0 mi E of ID46, Gooding, ID

Built 1964 Load: 14.9 t ADT: 25

NORTH BIRCH STREET

Poor

Over: LITTLE WOOD RIVER

IN SHOSHONE;N.BIRCH ST, Lincoln, ID

Built 1913 Load: 15.4 t ADT: 200

FALL CREEK RD

Poor

Over: FALL CREEK

0.5 S. 5.0 W. PINE, Elmore, ID

Built 1987 Load: 15.4 t ADT: 30

SAGE CREEK ROAD

Poor

Over: SAGE CREEK

0.7 S. 1.4 W. MIDVALE, Washington, ID

Built 1965 Load: 15.4 t ADT: 50

STC 6760;RED ROAD

Poor

Over: CAMAS CREEK

8.1 S. 0.4 W. KILGORE, Clark, ID

Built 1953 Load: 15.4 t ADT: 360

KILPATRICK BR. RD.

Poor

Over: SILVER CREEK

0.5 N. 3.5 W. PICABO, Blaine, ID

Built 1978 Load: 16.2 t ADT: 60

SMA 7406;17TH ST

Poor

Over: SAND CREEK

IN AMMON;17TH STREET, Bonneville, ID

Built 1957 Load: 16.3 t ADT: 19,500

NHS 7773;10TH AVE

Poor

Over: CITY ST;UPRR;CALDWELL OP

IN CALDWELL;10TH AVE, Canyon, ID

Built 1956 Load: 16.3 t ADT: 20,000

E. SUBLETTE ROAD

Poor

Over: PORTNEUF MARSH VAL.CNL

1.2 N. 0.5 E. ARIMO, Bannock, ID

Built 1968 Load: 16.3 t ADT: 50

RIDGEWAY ROAD

Poor

Over: C CANAL

2.0 S. 3.5 E. HAZELTON, Jerome, ID

Built 1963 Load: 16.3 t ADT: 9,750

SMITH FERRY DRIVE

Poor

Over: N.FK.PAYETTE RIVER

0.2 E. SMITHS FERRY, Valley, ID

Built 1959 Load: 16.3 t ADT: 90

STC 3007;UNITY RD

Poor

Over: WEISER RIVER

0.7 S. 5.6 E. WEISER, Washington, ID

Built 1910 Load: 16.3 t ADT: 170

RAPID LIGHTNING RD

Poor

Over: RAPID LIGHTNING CREEK

3.4 S. 6.8 E. SAMUELS, Bonner, ID

Built 1970 Load: 16.3 t ADT: 270

BUNKER AVE

Poor

Over: S.FK.COEUR DALENE RIVER

IN KELLOGG;BUNKER AVE, Shoshone, ID

Built 1971 Load: 16.3 t ADT: 1,900

N 4400 E (SHELTON)

Poor

Over: BURGESS CANAL

4.7 E. 0.6 S. RIGBY, Jefferson, ID

Built 1969 Load: 16.3 t ADT: 510

N. ST. CHARLES

Poor

Over: LEMHI RIVER

0.4 N. 0.3 E. SALMON, Lemhi, ID

Built 1948 Load: 16.3 t ADT: 310

COOPER PASS ROAD

Poor

Over: CANYON CREEK

0.5 N. 2.3 E. BURKE, Shoshone, ID

Built 2012 Load: 17.2 t ADT: 40

FS ROUTE NO. 409

Poor

Over: W.F. STEAMBOAT CREEK

W FK STEAMBOAT CR, Shoshone, ID

Built 1956 Load: 17.2 t ADT: 50

NO DATA ENTERED

Poor

Over: PANTHER CREEK

NO DATA ENTERED, Lemhi, ID

Built 1980 Load: 17.2 t ADT: 200

I 15B ;US 91

Poor

Over: BLACKFOOT RIVER

IN BLACKFOOT, Bingham, ID

Built 1936 Load: 18.1 t ADT: 6,900

250 WEST ROAD

Poor

Over: N. GOODING CANAL

7.2 N. 2.4 W. SHOSHONE, Lincoln, ID

Built 1975 Load: 18.1 t ADT: 20

SHEEP CAMP RD

Poor

Over: GRANDVIEW IRRIGATION CNL

1.3 E. GRANDVIEW, Owyhee, ID

Built 1991 Load: 18.1 t ADT: 60

SH 52

Poor

Over: SNAKE RIVER;PAYETTE BR.

ID-OR LINE;PAYETTE, Payette, ID

Built 1953 Load: 19.1 t ADT: 4,800

200 SOUTH ROAD

Poor

Over: CAMAS CREEK

1.8 S. 6.7 E. FAIRFIELD, Camas, ID

Built 1950 Load: 19.1 t ADT: 30

COLBURN CULVER RD

Poor

Over: PACK RIVER

1.0 N. 4.0 E. COLBURN, Bonner, ID

Built 1941 Load: 19.1 t ADT: 840

CUSTER MOTORWAY

Poor

Over: YANKEE FORK

NO DATA ENTERED, Custer, ID

Built 1992 Load: 19.1 t ADT: 100

NO DATA ENTERED

Poor

Over: NO DATA ENTERED

NO DATA ENTERED, Custer, ID

Built 1972 Load: 19.1 t ADT: 50

FDR

Poor

Over: SOUTH FORK BOISE RIVER

SKUNK CREEK-SO FK JUNCT., Camas, ID

Built 1989 Load: 19.1 t ADT: 12

STC2768;2400 E. RD

Poor

Over: MILNER GOODING CANAL

2.5 S. 4.5 E. HAZELTON, Jerome, ID

Built 1970 Load: 19.8 t ADT: 310

ROARING RIVER ROAD

Poor

Over: MIDDLE FORK BOISE RIVER

4.5 MI WSW DUTCH CR CABIN, Elmore, ID

Built 1957 Load: 19.8 t ADT: 20

STC2781;1300 S. RD

Poor

Over: THORN CREEK

5.0 N. 5.1 E. GOODING, Gooding, ID

Built 1955 Load: 20.0 t ADT: 340

OLD HWY 95

Poor

Over: LITTLE SALMON RIVER

0.3 W. NEW MEADOWS, Adams, ID

Built 1923 Load: 20.7 t ADT: 20

FS ROUTE NO. 456A

Poor

Over: N.F. ST JOE RIVER

LOOP CREEK, Shoshone, ID

Built 1935 Load: 20.7 t ADT: 50

COTTONWD-BANNOCK

Poor

Over: MORES CREEK

1 MI ESE OF IDAHO CITY, Boise, ID

Built 1962 Load: 20.7 t ADT: 30

US 30

Poor

Over: DRY CREEK

1.2 E. MURTAUGH, Twin Falls, ID

Built 1934 Load: 20.9 t ADT: 2,700

STC2744;1900 E. RD

Poor

Over: C CANAL

0.8 S. 0.6 W. HAZELTON, Jerome, ID

Built 1965 Load: 20.9 t ADT: 710

DIAMOND CREED ROAD

Poor

Over: BLACKFOOT RIVER

10.4 S. 2.5 E. WAYAN, Caribou, ID

Built 1971 Load: 20.9 t ADT: 55

200 EAST ROAD

Poor

Over: T.F.NORTHSIDE MAIN CNL

3.1 N. 2.0 E. JEROME, Jerome, ID

Built 1970 Load: 20.9 t ADT: 290

MAIN STREET SOUTH

Poor

Over: JIM FORD CREEK

IN WEIPPE;MAIN ST. SOUTH, Clearwater, ID

Built 1965 Load: 20.9 t ADT: 80

W 33RD S

Poor

Over: GREAT WESTERN CANAL

1.5 S. 4.8 W. IDAHO FALLS, Bonneville, ID

Built 1930 Load: 20.9 t ADT: 570

STC5752;CDA RVR RD

Poor

Over: COEUR DALENE RIVER

4.7 S. PRICHARD, Shoshone, ID

Built 1951 Load: 21.6 t ADT: 930

Showing 4,451-4,500 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.