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

200 SOUTH ROAD

Fair

Over: L CANAL

2.0 S. 5.7 E. JEROME, Jerome, ID

Built 2005 Load: 55.3 t ADT: 500

SE 11TH AVENUE

Fair

Over: D LINE CANAL

10.5S 3.4E NEW PLYMOUTH, Payette, ID

Built 1965 Load: 55.3 t ADT: 50

STIBNITE ROAD

Fair

Over: SUGAR CREEK

7.9 E. YELLOW PINE, Valley, ID

Built 1975 Load: 55.3 t ADT: 30

FS ROUTE NO. 209

Fair

Over: N.F. CDA RIVER

AT HORSE HAVEN, Kootenai, ID

Built 1950 Load: 55.7 t ADT: 50

US 30

Fair

Over: S COULEE CANAL

0.7 E. FILER, Twin Falls, ID

Built 1996 Load: 56.2 t ADT: 10,500

SMA 7273;LATAH ST

Fair

Over: RIDENBAUGH CANAL

IN BOISE;LATAH ST., Ada, ID

Built 1991 Load: 56.2 t ADT: 4,600

S. FLORIDA

Fair

Over: PHYLLIS CANAL

4.2 S. 1.2 E. CALDWELL, Canyon, ID

Built 2001 Load: 56.2 t ADT: 2,600

COW CREEK ROAD

Fair

Over: RUSH CREEK

4.7 N. 0.2 W. CAMBRIDGE, Washington, ID

Built 2004 Load: 56.2 t ADT: 50

US 20B

Fair

Over: TWIN GROVES CANAL

1.6 N. ST ANTHONY, Fremont, ID

Built 1992 Load: 57.2 t ADT: 1,400

US 95

Fair

Over: PARADISE CREEK

IN MOSCOW, Latah, ID

Built 2000 Load: 57.2 t ADT: 10,500

US 95

Fair

Over: WILDLIFE UNDERPASS

15.6 S. EASTPORT, Boundary, ID

Built 2004 Load: 57.2 t ADT: 1,100

SMA 7134;8TH ST.

Fair

Over: BRYDEN CANYON ROAD

IN LEWISTON, Nez Perce, ID

Built 1999 Load: 57.2 t ADT: 4,000

STC 6709; N 4200 E

Fair

Over: ISLAND CANAL

3.7 N 1.7 E RIGBY, Jefferson, ID

Built 2011 Load: 57.2 t ADT: 2,700

US 20B

Fair

Over: SALEM UNION CANAL

1.5 N. ST. ANTHONY, Fremont, ID

Built 1994 Load: 58.1 t ADT: 1,400

SH 34

Fair

Over: LITTLE BLACKFOOT RIVER

19.4 N. SODA SPRINGS, Caribou, ID

Built 1979 Load: 58.1 t ADT: 540

US 95

Fair

Over: WILDLIFE UNDERPASS

14.8 S. EASTPORT, Boundary, ID

Built 2004 Load: 58.1 t ADT: 1,100

HILLVIEW ROAD

Fair

Over: BISSEL CREEK

3.3 N. 4.1 W. EMMETT, Gem, ID

Built 1945 Load: 58.1 t ADT: 140

PARK RD; TAUTPHAUS

Fair

Over: BUTTE ARM CANAL

IN I.F.; TAUTPHAUS PARK, Bonneville, ID

Built 2005 Load: 58.1 t ADT: 840

STC3768;HUBBARD

Fair

Over: MASON CREEK

1.8 N. 1.9 E. KUNA, Ada, ID

Built 1992 Load: 59.0 t ADT: 390

WILLOW CREEK RD

Fair

Over: I 90 EB-WB;WILLOW CR. GS

2.5 E. MULLAN, Shoshone, ID

Built 1973 Load: 59.0 t ADT: 190

STC 1843; E 800 N

Fair

Over: BLACKFOOT CANAL

0.5 N 0.5 E FIRTH, Bingham, ID

Built 2006 Load: 59.9 t ADT: 2,400

STC 1843; E 800 N

Fair

Over: RESERVATION CANAL

0.5 N 0.5 E FIRTH, Bingham, ID

Built 2006 Load: 59.9 t ADT: 2,400

200 SOUTH ROAD

Fair

Over: L CANAL

2.0 S. 3.5 E. JEROME, Jerome, ID

Built 2004 Load: 59.9 t ADT: 5,000

200 NORTH ROAD

Fair

Over: S CANAL

1.5 W. 2.0 N. JEROME, Jerome, ID

Built 2001 Load: 59.9 t ADT: 450

SHOEPEG ROAD

Fair

Over: DEER CREEK

3.0 N. MIDVALE, Washington, ID

Built 1950 Load: 59.9 t ADT: 90

S FK GUARD STA RD

Fair

Over: PONY CREEK

15.5 N 4.0 W YELLOW PINE, Valley, ID

Built 2003 Load: 59.9 t ADT: 15

US 95

Fair

Over: WILDLIFE UNDERPASS

16.1 S. EASTPORT, Boundary, ID

Built 2004 Load: 60.8 t ADT: 1,100

STC 1850; RIVERTON

Fair

Over: BLACKFOOT RIVER

4.1 S 6.6 W BLACKFOOT, Bingham, ID

Built 2006 Load: 60.8 t ADT: 110

STC2721;2200 E. RD

Fair

Over: CEDAR DRAW

1.3 S. FILER;3765N-2200E, Twin Falls, ID

Built 1964 Load: 60.8 t ADT: 1,200

1500 N WOODVILLE

Fair

Over: GREAT WESTERN CANAL

2.0 N 2.5 W SHELLEY, Bingham, ID

Built 2001 Load: 61.7 t ADT: 130

3600 NORTH ROAD

Fair

Over: HIGH LINE CANAL

5.4 S. 3.0 E. BUHL, Twin Falls, ID

Built 1936 Load: 61.7 t ADT: 70

UPPERDALE ROAD

Fair

Over: HORNET CREEK

6.1 N. 7.1 W. COUNCIL, Adams, ID

Built 1960 Load: 61.7 t ADT: 30

E 200 N

Fair

Over: FARMERS FRIEND CANAL

1.5 W. WILFORD, Fremont, ID

Built 2016 Load: 61.9 t ADT: 1,100

US 26

Fair

Over: S. GOODING MAIN CANAL

4.2 E. GOODING, Gooding, ID

Built 2008 Load: 62.6 t ADT: 1,900

STC3728;LAKE HAZEL

Fair

Over: RAWSON CANAL

4.5 S. 0.1 E. MERIDIAN, Ada, ID

Built 1993 Load: 62.6 t ADT: 3,300

S3944;FARM TO MRKT

Fair

Over: BOULDER CREEK

2.6 N. 1.5 E. DONNELLY, Valley, ID

Built 1996 Load: 62.6 t ADT: 350

I 15B ;BROADWAY ST

Fair

Over: PORTER CANAL

IN IDAHO FALLS;BROADWAY, Bonneville, ID

Built 1987 Load: 63.5 t ADT: 24,000

BUNCH DRIVE

Fair

Over: M. FK. PAYETTE RIVER

5.5 N. 2.0 E. CROUCH, Boise, ID

Built 1995 Load: 63.5 t ADT: 50

SH 33 SPUR

Fair

Over: US 20;SH 33 SPUR IC

0.5 N. SUGAR CITY, Madison, ID

Built 2001 Load: 64.4 t ADT: 2,200

TARGEE STREET

Fair

Over: FIVE MILE CREEK

IN BOISE;E/O MAPLE GROVE, Ada, ID

Built 1990 Load: 64.4 t ADT: 1,100

STC 3782;MALT RD

Fair

Over: LOW LINE CANAL

3.5 N. 3.0 E. MARSING, Canyon, ID

Built 1998 Load: 64.4 t ADT: 330

SH 21

Fair

Over: MORES CR.;AT MINNIHA CR

8.9 S. IDAHO CITY, Boise, ID

Built 1990 Load: 65.3 t ADT: 2,000

STC 9273;CASTLE DR

Fair

Over: FARMERS UNION CANAL

IN BOISE;CASTLE DRIVE, Ada, ID

Built 1992 Load: 65.3 t ADT: 3,200

S3944;FARM TO MRKT

Fair

Over: STOVER CREEK

1.6 N. 1.5 E. DONNELLY, Valley, ID

Built 1996 Load: 66.1 t ADT: 350

US 20 EB-WB

Fair

Over: SH 48;RIGBY GS

IN RIGBY, Jefferson, ID

Built 1976 Load: 66.2 t ADT: 20,000

CARR ROAD

Fair

Over: LITTLE SALMON RIVER

2.0 S. 1.2 W. NEW MEADOW, Adams, ID

Built 2000 Load: 66.2 t ADT: 10

ROUTE 468-A

Fair

Over: DEEP CR

NO DATA ENTERED, Idaho, ID

Built 1938 Load: 66.7 t ADT: 10

I 184 EB OFF RAMP

Fair

Over: I 184 EB ON RAMP

4.2 W. BOISE, Ada, ID

Built 2003 Load: 67.1 t ADT: 4,000

SH 43

Fair

Over: ANDERSON CANAL

1.4 S. UCON, Bonneville, ID

Built 1994 Load: 67.1 t ADT: 6,100

SLICKPOO ROAD

Fair

Over: MISSION CR;M.WITTMAN BR

3.8 S. 1.6 W. CULDESAC, Nez Perce, ID

Built 1987 Load: 67.1 t ADT: 50

Showing 2,901-2,950 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.