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

SH 75

Fair

Over: VALLEY CREEK

0.5 N. STANLEY, Custer, ID

Built 1977 Load: 20.0 t ADT: 660

US 95

Fair

Over: SNAKE RIVER;HOMEDALE BR.

AT HOMEDALE ECL, Owyhee, ID

Built 1969 Load: 20.0 t ADT: 11,000

STC2739;3800 E. RD

Fair

Over: LATERAL 10

1.4 N. 0.3 W. HANSEN, Twin Falls, ID

Built 1920 Load: 20.0 t ADT: 2,700

STC2757;NORTH ROAD

Fair

Over: U CANAL

3.0 N. JEROME, Jerome, ID

Built 1954 Load: 20.0 t ADT: 1,500

STC2815;WARM SPRGS

Fair

Over: WARM SPRINGS CREEK

2.6 W. KETCHUM, Blaine, ID

Built 1955 Load: 20.0 t ADT: 540

STC8215;WEISER RVR

Fair

Over: MANNS CREEK

0.3 S. 5.1 E. WEISER, Washington, ID

Built 1954 Load: 20.0 t ADT: 320

SMA7316;N 5TH EAST

Fair

Over: IDAHO CANAL

1.5 N. IDAHO FALLS, Bonneville, ID

Built 1957 Load: 20.0 t ADT: 6,000

STC4755;TAMMANY CR

Fair

Over: TAMMANY CREEK

0.3 S. LEWISTON SCL, Nez Perce, ID

Built 1987 Load: 20.0 t ADT: 2,600

OSBORN LOOP

Fair

Over: FALL CREEK

2.0 E. EXIT 21(COLDWATER), Power, ID

Built 1981 Load: 20.0 t ADT: 95

2500 EAST ROAD

Fair

Over: GOODING MAIN CANAL

6.0 N. 6.0 E. GOODING, Gooding, ID

Built 1930 Load: 20.0 t ADT: 30

1600 EAST ROAD

Fair

Over: DRY CREEK

3.4 N. 3.0 W. GOODING, Gooding, ID

Built 1930 Load: 20.0 t ADT: 30

3300 EAST RD

Fair

Over: LOW LINE CANAL

5.1 S. 3.5 E. TWIN FALLS, Twin Falls, ID

Built 1981 Load: 20.0 t ADT: 140

BLUFF LANE

Fair

Over: RIVERSIDE CANAL

2.8 N. 1.4 E. WILDER, Canyon, ID

Built 1985 Load: 20.0 t ADT: 50

SMA3735;PRPLE SAGE

Fair

Over: SEBREE CANAL

0.7 N. 0.9 E. NOTUS, Canyon, ID

Built 1982 Load: 20.0 t ADT: 440

OLD HWY ROAD

Fair

Over: BEAVER CREEK

1.2 E. MIDVALE, Washington, ID

Built 1930 Load: 20.0 t ADT: 220

MOTHER LODE

Fair

Over: AMERICAN R;SE.ELK CITY B

1.1 S. 0.3 E. ELK CITY, Idaho, ID

Built 1936 Load: 20.0 t ADT: 50

STC4751;CTTNWD CRK

Fair

Over: COTTONWOOD CREEK

3.8 N. 0.8 E. CULDESAC, Nez Perce, ID

Built 1968 Load: 20.0 t ADT: 40

RAPID LIGHTNING RD

Fair

Over: RAPID LIGHTNING CREEK

3.4 S. 5.4 E. SAMUELS, Bonner, ID

Built 1970 Load: 20.0 t ADT: 270

N 3185 E

Fair

Over: FALL RIVER

0.3 N. 2.6 E. CHESTER, Fremont, ID

Built 1977 Load: 20.0 t ADT: 50

N 4950 E

Fair

Over: FARMERS FRIEND CANAL

0.4 N. 3.1 E. RIRIE, Jefferson, ID

Built 1950 Load: 20.0 t ADT: 550

SMA 7288;HILL RD

Fair

Over: FARMERS UNION CANAL

IN BOISE, Ada, ID

Built 1963 Load: 20.0 t ADT: 3,800

FS ROUTE 2354

Fair

Over: BIG CREEK

3.5 MI FROM BIG CREEK ID, Shoshone, ID

Built 1936 Load: 20.1 t ADT: 50

FS ROUTE NO. 412

Fair

Over: CDA RIVER

23.4 MI FROM SHOSHONE W.C, Shoshone, ID

Built 1935 Load: 20.1 t ADT: 50

FS ROUTE NO. 208

Fair

Over: CDA RIVER

22.8 MI. FROM BABINS JCT., Shoshone, ID

Built 1974 Load: 20.1 t ADT: 50

FS ROUTE NO. 715

Fair

Over: ST JOE RIVER

ST. JOE RIVER, Shoshone, ID

Built 1953 Load: 20.1 t ADT: 50

QUEENS RIVER ROAD

Fair

Over: QUEENS RIVER

3.5 MI NW OF ATLANTA ID, Elmore, ID

Built 1965 Load: 20.1 t ADT: 15

ARCHIE CK. ROAD

Fair

Over: SOUTH FORK PAYETTE RIVER

5 MI EAST OF LOWMAN IDAHO, Boise, ID

Built 1962 Load: 20.1 t ADT: 40

SAWMILL CANYON RD

Fair

Over: LITTLE LOST RIVER

40.5 MI. NNW OF HOWE ID, Custer, ID

Built 1957 Load: 20.1 t ADT: 40

FS ROUTE NO. 412

Fair

Over: JORDAN CREEK

JORDAN CREEK, Shoshone, ID

Built 1957 Load: 20.4 t ADT: 50

FDR 250

Fair

Over: LAKE CREEK

JCT LAKE CR / NF CLW RIV, Clearwater, ID

Built 1954 Load: 20.4 t ADT: 80

NO DATA ENTERED

Fair

Over: NORTH FORK SALMON

NO DATA ENTERED, Lemhi, ID

Built 1956 Load: 20.4 t ADT: 50

NO DATA ENTERED

Fair

Over: OWL CREEK

NO DATA ENTERED, Lemhi, ID

Built 1959 Load: 20.4 t ADT: 200

FULLER ROAD

Fair

Over: BLACK CANYON CANAL

1.6 N. 3.4 E. EMMETT, Gem, ID

Built 1976 Load: 20.7 t ADT: 100

STC9584;CHERRY LN

Fair

Over: BLACK CANYON CANAL

1.3 S. 1.8 E. EMMETT, Gem, ID

Built 1979 Load: 20.7 t ADT: 350

FROZEN DOG ROAD

Fair

Over: BLACK CANYON CANAL

1.2 N. 3.1 E. EMMETT, Gem, ID

Built 1977 Load: 20.7 t ADT: 150

POPLAR ROAD

Fair

Over: W.FK.ST MARIES RIVER

AT CLARKIA, Shoshone, ID

Built 1957 Load: 20.7 t ADT: 330

N 4200 E RD

Fair

Over: BURGESS CNL BR

0.3 S. 2.6 E. RIGBY, Jefferson, ID

Built 1969 Load: 20.7 t ADT: 160

FS ROUTE 1205

Fair

Over: ST JOE RIVER

RED IVES WORKCENTER, Shoshone, ID

Built 1935 Load: 20.7 t ADT: 50

BEAVER CREEK ROAD

Fair

Over: SEAFOAM CREEK

NO DATA ENTERED, Custer, ID

Built 1968 Load: 20.7 t ADT: 10

ROAD

Fair

Over: BEAR VALLEY CREEK

NO DATA ENTERED, Lemhi, ID

Built 1960 Load: 20.7 t ADT: 50

US 30 EBL SPUR

Fair

Over: SNAKE R;FRUITLAND BRIDGE

0.6 W. FRUITLAND, Payette, ID

Built 1967 Load: 20.9 t ADT: 27,000

SH 55

Fair

Over: LAKE FORK CREEK CANAL

IN LAKE FORK, Valley, ID

Built 1998 Load: 20.9 t ADT: 6,300

US 93

Fair

Over: SALMON RIVER;SALMON BR.

AT SALMON, Lemhi, ID

Built 1926 Load: 20.9 t ADT: 8,500

STC 1702;SAMARIA

Fair

Over: MALAD RIVER;E.SAMARIA BR

2.2 S. 4.3 E. SAMARIA, Oneida, ID

Built 1990 Load: 20.9 t ADT: 250

STC 1834; W 200 S

Fair

Over: ABERDEEN SPRINGFIELD CNL

3.6 N. 1.6 E. PINGREE, Bingham, ID

Built 1992 Load: 20.9 t ADT: 270

STC 1847; E 1250 N

Fair

Over: SNAKE RIVER;W.SHELLEY BR

2.1 W. SHELLEY, Bingham, ID

Built 1965 Load: 20.9 t ADT: 3,200

SMA 7721; RIVERTON

Fair

Over: BLACKFOOT RIVER OVERFLOW

1.1 S. 2.3 W. BLACKFOOT, Bingham, ID

Built 1964 Load: 20.9 t ADT: 420

STC 1851; TAYLOR

Fair

Over: E.BR.SNAKE R.VALLEY CNL

1.1 E. SHELLEY;910E-1300N, Bingham, ID

Built 1988 Load: 20.9 t ADT: 1,700

STC 1851; 1300 N

Fair

Over: LITTLE SAND CREEK

2.5 E. SHELLEY, Bingham, ID

Built 1968 Load: 20.9 t ADT: 1,700

STC 1851; E 1300 N

Fair

Over: SAND CREEK

3.3 E. SHELLEY, Bingham, ID

Built 1988 Load: 20.9 t ADT: 1,700

Showing 451-500 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.