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

SLAUGH ROAD;S2750W

Fair

Over: LOW LINE CANAL

2.1 N. ABERDEEN, Bingham, ID

Built 1973 Load: 28.1 t ADT: 100

STC 1840;WOLVERINE

Fair

Over: SAND CREEK

1.5 S. 1.3 E. FIRTH, Bingham, ID

Built 1964 Load: 28.1 t ADT: 520

WASHINGTON RD;300W

Fair

Over: ABERDEEN SPRINGFIELD CNL

5.0 N. 0.6 W. BLACKFOOT, Bingham, ID

Built 1967 Load: 28.1 t ADT: 200

STC 1840:WOLVERINE

Fair

Over: IDAHO CANAL

1.5S. 3.6E. FIRTH, Bingham, ID

Built 2002 Load: 28.1 t ADT: 290

2750 WEST ROAD

Fair

Over: LOW LINE CANAL

1.0 S. ABERDEEN;2750W, Bingham, ID

Built 1965 Load: 28.1 t ADT: 200

VALLEY VIEW DRIVE

Fair

Over: SODA CANAL

1.1 N. 2.2 W.SODA SPRINGS, Caribou, ID

Built 1980 Load: 28.1 t ADT: 60

HALLING ROAD

Fair

Over: ROCK CREEK

2.0 N. 1.3 W. ROCKLAND, Power, ID

Built 1971 Load: 28.1 t ADT: 100

LABRADOR LANE

Fair

Over: BELLEVUE CANAL

1.3 S. 0.6 E. BELLEVUE, Blaine, ID

Built 2000 Load: 28.1 t ADT: 100

LITTLE WOOD RES RD

Fair

Over: LITTLE WOOD RIVER

7.3 N. 3.4 W. CAREY, Blaine, ID

Built 1991 Load: 28.1 t ADT: 80

50 EAST ROAD

Fair

Over: J CANAL;SE.BURLEY BR

6.1S 0.5E BURLEY;580S-50E, Cassia, ID

Built 1975 Load: 28.1 t ADT: 100

2000 SOUTH ROAD

Fair

Over: T.F.NORTHSIDE MAIN CNL

2.0 S. 0.5 E. GOODING, Gooding, ID

Built 1930 Load: 28.1 t ADT: 150

1700 EAST ROAD

Fair

Over: DOG CREEK

4.9 N. 2.0 W. GOODING, Gooding, ID

Built 1974 Load: 28.1 t ADT: 80

3425 NORTH ROAD

Fair

Over: DRY CREEK

0.9 E. MURTAUGH, Twin Falls, ID

Built 1965 Load: 28.1 t ADT: 100

2600 EAST RD

Fair

Over: LOW LINE CANAL

2.3 S. 3.5 W. TWIN FALLS, Twin Falls, ID

Built 1968 Load: 28.1 t ADT: 210

2500 NORTH ROAD

Fair

Over: SALMON LATERAL NO.1

0.5 N. 2.0 E. HOLLISTER, Twin Falls, ID

Built 1978 Load: 28.1 t ADT: 40

4000 NORTH RD

Fair

Over: LOW LINE CANAL

1.4 S. 5.4 W. BUHL, Twin Falls, ID

Built 1966 Load: 28.1 t ADT: 100

BETHEL COURT

Fair

Over: RIDENBAUGH CANAL

IN BOISE;BETHEL CT, Ada, ID

Built 1981 Load: 28.1 t ADT: 150

STC 9163;APPLE ST

Fair

Over: RIDENBAUGH CANAL

IN BOISE;APPLE STREET, Ada, ID

Built 1992 Load: 28.1 t ADT: 6,900

STC3761;PLUMMER RD

Fair

Over: MIDDLETON CANAL

0.3 N. 1.0 E. STAR, Ada, ID

Built 1971 Load: 28.1 t ADT: 3,200

SMA 9833;MILWAUKEE

Fair

Over: RIDENBAUGH CANAL

IN BOISE;MILWAUKEE ST, Ada, ID

Built 1979 Load: 28.1 t ADT: 21,000

SMA3613;MCMILLAN

Fair

Over: PHYLLIS CANAL

3.0 S. 0.3 W. STAR, Ada, ID

Built 1967 Load: 28.1 t ADT: 1,300

SMA 7243;BEACON ST

Fair

Over: LOGGERS CREEK

IN BOISE, Ada, ID

Built 1977 Load: 28.1 t ADT: 6,300

LOCUST GROVE ROAD

Fair

Over: MORA CANAL

2.0 S. 2.3 E. KUNA, Ada, ID

Built 1976 Load: 28.1 t ADT: 350

STC 7673;GOWEN RD

Fair

Over: FIVE MILE CREEK

ON GOWEN RD.;S.CAMEO ST., Ada, ID

Built 1940 Load: 28.1 t ADT: 3,000

S3784;LOCUST GROVE

Fair

Over: MASON CREEK FEEDER CANAL

1.6 N. 2.3 E. KUNA, Ada, ID

Built 1969 Load: 28.1 t ADT: 610

SMA 7363;EMERALD

Fair

Over: RIDENBAUGH CANAL

IN BOISE;EMERALD ST, Ada, ID

Built 1979 Load: 28.1 t ADT: 16,500

STC 3771;STROEBEL

Fair

Over: NORTH INDIAN CREEK

0.4 S. 1.8 E. KUNA, Ada, ID

Built 1982 Load: 28.1 t ADT: 400

S9783;LOCUST GROVE

Fair

Over: EIGHT MILE LATERAL

IN BOISE, Ada, ID

Built 2000 Load: 28.1 t ADT: 11,500

STC 9693;SEAMANS G

Fair

Over: FARMERS UNION CANAL

SEAMANS GULCH;HILL RD, Ada, ID

Built 1992 Load: 28.1 t ADT: 4,900

STC3928;S EAGLE RD

Fair

Over: KUNA CANAL

0.1 S. 3.3 E. KUNA, Ada, ID

Built 1988 Load: 28.1 t ADT: 1,100

CHRISTINE STREET

Fair

Over: SETTLERS CANAL

IN BOISE;CHRISTINE ST., Ada, ID

Built 1968 Load: 28.1 t ADT: 500

SMA9213;VETERANS P

Fair

Over: FARMERS UNION CANAL

IN BOISE;VETERANS PARKWAY, Ada, ID

Built 1985 Load: 28.1 t ADT: 21,500

ZIMS RD

Fair

Over: LITTLE SALMON RIVER

4.7 N. 0.4 W. NEW MEADOWS, Adams, ID

Built 1930 Load: 28.1 t ADT: 100

SUMMIT FLAT ROAD

Fair

Over: CLEAR CREEK

0.3 E. PIONEERVILLE, Boise, ID

Built 1974 Load: 28.1 t ADT: 50

DAGGET CREEK RD

Fair

Over: MORES CREEK

7.0 W. 10.5 S. IDAHO CITY, Boise, ID

Built 1991 Load: 28.1 t ADT: 100

TRACK ROAD

Fair

Over: MORA CANAL

9.4 S. 1.1 E. NAMPA, Canyon, ID

Built 1983 Load: 28.1 t ADT: 200

TUCKER ROAD

Fair

Over: RIVERSIDE CANAL

1.1 N. 3.3 E. WILDER, Canyon, ID

Built 1999 Load: 28.1 t ADT: 20

STC3747;W LOCUST L

Fair

Over: DEER FLAT HIGH LINE CNL

3.2 S. 4.9 W. NAMPA, Canyon, ID

Built 1997 Load: 28.1 t ADT: 1,400

POWER LINE ROAD

Fair

Over: NEW YORK CANAL

4.8 S. 0.4 E. NAMPA, Canyon, ID

Built 1919 Load: 28.1 t ADT: 650

STC 3839;BATT CRNR

Fair

Over: GOLDEN GATE CANAL

0.2 S. 0.5 W. WILDER, Canyon, ID

Built 2000 Load: 28.1 t ADT: 220

STC 3725;MISSOURI

Fair

Over: MORA CANAL

6.2S 4.1W NAMPA CITY CTR, Canyon, ID

Built 1984 Load: 28.1 t ADT: 1,200

FOUNTAIN ROAD

Fair

Over: SEBREE CANAL

2.7 N. 2.8 W. NOTUS, Canyon, ID

Built 1994 Load: 28.1 t ADT: 100

STC3742;WAMSTAD RD

Fair

Over: BOISE RIVER

1.2 S. 0.3 W. PARMA, Canyon, ID

Built 1975 Load: 28.1 t ADT: 2,600

E. SIMPLOT BLVD.

Fair

Over: INDIAN CREEK

IN CALDWELL, Canyon, ID

Built 1965 Load: 28.1 t ADT: 280

LINDEN ROAD

Fair

Over: MASON CREEK

1.0 S. 4.5 E. CALDWELL, Canyon, ID

Built 1974 Load: 28.1 t ADT: 6,700

10TH AVE N.

Fair

Over: INDIAN CREEK

IN NAMPA;10TH AVE N, Canyon, ID

Built 1973 Load: 28.1 t ADT: 1,100

HILL ROAD

Fair

Over: KING HILL DITCH

1.8 S. 0.7 E. KING HILL, Elmore, ID

Built 1969 Load: 28.1 t ADT: 60

MONTGOMERY RD

Fair

Over: KING HILL CREEK

0.7 N. 1.4 W. KING HILL, Elmore, ID

Built 1963 Load: 28.1 t ADT: 30

W SOUTH SLOPE RD

Fair

Over: FARMERS COOP CANAL

1.6 S. 5.1 W. EMMETT, Gem, ID

Built 1955 Load: 28.1 t ADT: 680

3 CREEK ROAD

Fair

Over: E.FK.JARBIDGE RIVER

0.1 W. MURPHY HOT SPRING, Owyhee, ID

Built 1979 Load: 28.1 t ADT: 30

Showing 1,401-1,450 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.