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 48

Fair

Over: RUDY CANAL

7.6 E. RIGBY, Jefferson, ID

Built 1986 Load: 39.9 t ADT: 2,000

SH 52

Fair

Over: NOBLE CANAL

8.4 W. EMMETT, Gem, ID

Built 1990 Load: 39.9 t ADT: 3,000

I 84 WBL

Fair

Over: BODENHEIMER ROAD GS

11.1 E. TWIN FALLS, Jerome, ID

Built 1966 Load: 39.9 t ADT: 12,000

I 84 EBL

Fair

Over: STC2767;VALLEY ROAD IC

19.7 W. BURLEY, Jerome, ID

Built 1966 Load: 39.9 t ADT: 12,000

I 84 WBL

Fair

Over: STC2767;VALLEY ROAD IC

19.7 W. BURLEY, Jerome, ID

Built 1966 Load: 39.9 t ADT: 12,000

I 84 EBL

Fair

Over: SHODDE ROAD GS

5.4 W. BURLEY, Minidoka, ID

Built 1966 Load: 39.9 t ADT: 11,000

I 84 WBL

Fair

Over: SHODDE ROAD GS

5.4 W. BURLEY, Minidoka, ID

Built 1966 Load: 39.9 t ADT: 11,000

I 84

Fair

Over: JUNIPER RD;GS NO.1

3.1 E. SUBLETT, Cassia, ID

Built 1968 Load: 39.9 t ADT: 11,000

SH 33

Fair

Over: OWSLEY CANAL

IN MUD LAKE, Jefferson, ID

Built 1995 Load: 39.9 t ADT: 3,100

I 90

Fair

Over: POTLATCH HILL RD. GS

0.5 S. COEUR DALENE, Kootenai, ID

Built 1992 Load: 39.9 t ADT: 19,500

YELLOWSTONE TRAIL

Fair

Over: I90;YELLOWSTONE TRAIL GS

2.5S. 2.5E. COEUR DALENE, Kootenai, ID

Built 1991 Load: 39.9 t ADT: 350

SMA7235;NW BLVD

Fair

Over: I 90 EB-WB;NW BLVD IC

COEUR D ALENE WCL, Kootenai, ID

Built 2001 Load: 39.9 t ADT: 39,500

SH 87

Fair

Over: HOWARD CREEK

9.4 N. MACKS INN, Fremont, ID

Built 2005 Load: 39.9 t ADT: 2,400

US 93

Fair

Over: BIG LOST RIVER

0.9 S. MOORE, Butte, ID

Built 1962 Load: 39.9 t ADT: 2,400

US 95

Fair

Over: MANNS CREEK

10.0 N. WEISER NCL, Washington, ID

Built 2004 Load: 39.9 t ADT: 4,300

US 95

Fair

Over: LAWYERS CANYON CREEK

5.0 S. CRAIGMONT, Idaho, ID

Built 1991 Load: 39.9 t ADT: 3,300

US 95

Fair

Over: LAPWAI CREEK

1 N. LAPWAI, Nez Perce, ID

Built 1964 Load: 39.9 t ADT: 6,800

US 95

Fair

Over: LAPWAI CREEK

SPAULDING CITY LIMITS, Nez Perce, ID

Built 1964 Load: 39.9 t ADT: 6,800

US 95

Fair

Over: US 12;US 12-95 IC

6.1 E. LEWISTON, Nez Perce, ID

Built 1964 Load: 39.9 t ADT: 11,000

SH 3

Fair

Over: ST MARIES RR

11.8 S. ST MARIES, Benewah, ID

Built 1961 Load: 39.9 t ADT: 1,700

STC 1809; N BEACH

Fair

Over: RAINBOW CANAL;MUD LAKE

0.8 N. 4.5 E. ST CHARLES, Bear Lake, ID

Built 1968 Load: 39.9 t ADT: 1,200

STC2745;3700 NORTH

Fair

Over: TWIN FALLS MAIN CANAL

2.8 N. 1.5 W. MURTAUGH, Twin Falls, ID

Built 1971 Load: 39.9 t ADT: 450

STP 9183;TEN MILE

Fair

Over: FUTURE NORTH CROSSING

1.2 S 2.1 W OF MERIDIAN, Ada, ID

Built 2011 Load: 39.9 t ADT: 33,000

CLARK STREET

Fair

Over: PORTNEUF RIVER

IN POCATELLO; CLARK ST., Bannock, ID

Built 1998 Load: 39.9 t ADT: 400

DEGUILLIO RD

Fair

Over: ABERDEEN SPRINGFIELD CNL

0.3 S. 0.9 W. PINGREE, Bingham, ID

Built 2018 Load: 39.9 t ADT: 100

PARK RD; S 5TH W

Fair

Over: IDAHO CANAL

1.3 S. 4.0 E. SHELLEY, Bingham, ID

Built 1982 Load: 39.9 t ADT: 90

LAST CHANCE LANE

Fair

Over: TANNER CANAL;NE.GRACE BR

1.4 N. 0.6 E. GRACE, Caribou, ID

Built 1958 Load: 39.9 t ADT: 50

150 WEST ROAD

Fair

Over: N. GOODING CANAL

7.2 N. 1.4 W. SHOSHONE, Lincoln, ID

Built 1962 Load: 39.9 t ADT: 20

STC 7832;H STREET

Fair

Over: C CANAL

IN RUPERT;H STREET, Minidoka, ID

Built 1965 Load: 39.9 t ADT: 1,900

3500 NORTH ROAD

Fair

Over: DEEP CREEK

6.4 S. 5.2 W. BUHL, Twin Falls, ID

Built 1965 Load: 39.9 t ADT: 50

BANKS GRADE

Fair

Over: N. FK. PAYETTE RIVER

AT BANKS, Boise, ID

Built 1957 Load: 39.9 t ADT: 590

SMA3343;LOCUST LN

Fair

Over: NEW YORK CANAL

3.2S 3.7E NAMPA CITY CTR, Canyon, ID

Built 1988 Load: 39.9 t ADT: 1,100

COUNTY ROAD

Fair

Over: I 90;SMELTERVILLE IC

0.3 N. 0.1 W.SMELTERVILLE, Shoshone, ID

Built 1964 Load: 39.9 t ADT: 3,600

FS ROUTE N0. 812

Fair

Over: LEIBERG CREEK

AT HEMLOCK CREEK, Kootenai, ID

Built 1959 Load: 39.9 t ADT: 50

FS ROUTE NO. 281

Fair

Over: SMITH CREEK

SMITH CREEK, Boundary, ID

Built 1974 Load: 39.9 t ADT: 50

FDR 705

Fair

Over: ISABELLA CREEK

39 MILES FROM PIERCE ID, Clearwater, ID

Built 1969 Load: 39.9 t ADT: 20

NFSR 50446

Fair

Over: FISHER CREEK

NO DATA ENTERED, Valley, ID

Built 1965 Load: 39.9 t ADT: 50

IRR BIA RTE 187

Fair

Over: BANNOCK CREEK

.4K N&.8 K W.OF 161 & I15, Power, ID

Built 1971 Load: 40.1 t ADT: 55

FS ROUTE NO. 208

Fair

Over: CINNAMON CREEK

23.6 MI FROM BABINS JCT., Shoshone, ID

Built 1974 Load: 40.2 t ADT: 40

FOREST ROAD 443

Fair

Over: AMERICAN RIVER

4 MILES NORTH OF ELK CITY, Idaho, ID

Built 1965 Load: 40.2 t ADT: 50

FS ROUTE NO. 437

Fair

Over: N.F. HAYDEN CR

NF HAYDEN CREEK, Kootenai, ID

Built 1953 Load: 40.5 t ADT: 50

SH 5

Fair

Over: BENEWAH CREEK

@ CHATCOLET ECL, Benewah, ID

Built 1996 Load: 40.8 t ADT: 3,400

STP 7343;MAIN ST

Fair

Over: BOISE RIVER

IN BOISE;MAIN ST. WBL, Ada, ID

Built 1965 Load: 40.8 t ADT: 14,000

SH 50

Fair

Over: SNAKE RIVER;HANSEN BR.

8.3 E. TWIN FALLS, Twin Falls, ID

Built 1966 Load: 40.8 t ADT: 8,700

SH 52

Fair

Over: B LATERAL CANAL

14.9 W. EMMETT, Payette, ID

Built 1990 Load: 40.8 t ADT: 3,200

SH 52

Fair

Over: DRAIN DITCH

5.6 W. EMMETT, Gem, ID

Built 1988 Load: 40.8 t ADT: 3,400

SH 78

Fair

Over: SNAKE R.;INDIAN COVE BR.

4.1 W. HAMMETT, Owyhee, ID

Built 1967 Load: 40.8 t ADT: 460

I 84 EBL

Fair

Over: MAIN NORTHSIDE CANAL

13.9 W. BURLEY, Jerome, ID

Built 1966 Load: 40.8 t ADT: 11,750

I 84 WBL

Fair

Over: CO.RD.;GS NO.3

13.1 E. SUBLETT, Cassia, ID

Built 1968 Load: 40.8 t ADT: 5,500

SH 33

Fair

Over: I 15 NB-SB;SAGE JCT IC

8.5 N. ROBERTS, Jefferson, ID

Built 1995 Load: 40.8 t ADT: 3,900

Showing 2,501-2,550 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.