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

MICHAUD ROAD

Fair

Over: TAGHEE CANAL

7.7N 13.7E AMERICAN FALLS, Power, ID

Built 1973 Load: 17.2 t ADT: 80

NORTH ROAD

Fair

Over: DRY CREEK

5.2 N. 3.6 W. GOODING, Gooding, ID

Built 1930 Load: 17.2 t ADT: 30

2400 EAST ROAD

Fair

Over: GOODING MAIN CANAL

5.8 N. 5.0 E. GOODING, Gooding, ID

Built 1930 Load: 17.2 t ADT: 30

2300 EAST ROAD

Fair

Over: BIG WOOD RIVER

3.8 N. 3.8 E. GOODING, Gooding, ID

Built 1930 Load: 17.2 t ADT: 20

2300 EAST ROAD

Fair

Over: LITTLE WOOD RIVER

0.2 S. 4.0 E. GOODING, Gooding, ID

Built 1930 Load: 17.2 t ADT: 300

EDEN ROAD

Fair

Over: C CANAL

2.6 S. EDEN, Jerome, ID

Built 1955 Load: 17.2 t ADT: 200

S3792;UPPR PLEASNT

Fair

Over: DEER FLAT CANAL

2.0 S. 2.7 E. WILDER, Canyon, ID

Built 1989 Load: 17.2 t ADT: 230

BOISE STREET

Fair

Over: MILL SLOUGH

AT MIDDLETON SCL, Canyon, ID

Built 1981 Load: 17.2 t ADT: 200

STC 3809;MIDDLE FK

Fair

Over: M.FK.BOISE RIVER;LOFTUS

6.2 S. 12.1 W.DUTCH CR RS, Elmore, ID

Built 1962 Load: 17.2 t ADT: 30

MDL POTLATCH CR RD

Fair

Over: MIDDLE POTLATCH CREEK

2.8 N. 9.8 E. JULIAETTA, Latah, ID

Built 1940 Load: 17.2 t ADT: 30

MOSER ROAD

Fair

Over: COW CREEK

1.5 S. 4.4 W. GENESEE, Nez Perce, ID

Built 1970 Load: 17.2 t ADT: 30

RAPID LIGHTNING RD

Fair

Over: RAPID LIGHTNING CREEK

3.2 S. 7.4 E. SAMUELS, Bonner, ID

Built 1974 Load: 17.2 t ADT: 270

SQUAW CREEK RD

Fair

Over: SQUAW CREEK

2.9 N. 3.8 W. CLAYTON, Custer, ID

Built 1960 Load: 17.2 t ADT: 300

COOPER PASS ROAD

Fair

Over: MILITARY GULCH

0.5 N. 2.3 E. BURKE, Shoshone, ID

Built 2012 Load: 17.2 t ADT: 40

FS ROUTE NO. 2236

Fair

Over: GROUSE CREEK

GROUSE CREEK, Bonner, ID

Built 1971 Load: 17.5 t ADT: 50

FOREST ROAD 421

Fair

Over: MALLARD CREEK

NO DATA ENTERED, Idaho, ID

Built 1992 Load: 17.5 t ADT: 50

LIGHTENING CR RD

Fair

Over: M. FK. PAYETTE

8 MI NORTH OF CROUCH ID, Boise, ID

Built 1964 Load: 17.5 t ADT: 50

NO DATA ENTERED

Fair

Over: COUGAR CREEK

NO DATA ENTERED, Valley, ID

Built 1970 Load: 17.5 t ADT: 50

CUSTER MOTORWAY

Fair

Over: YANKEE FORK

NO DATA ENTERED, Custer, ID

Built 2004 Load: 17.5 t ADT: 100

FS ROUTE NO. 300A

Fair

Over: N.F. ST JOE RIVER

3.5 MILES FROM AVERY ID, Shoshone, ID

Built 1935 Load: 17.8 t ADT: 50

ROAD

Fair

Over: PALISADES CREEK

NO DATA ENTERED, Bonneville, ID

Built 1975 Load: 17.8 t ADT: 50

US 20 26;FAP 21SPR

Fair

Over: SNAKE RIVER;NYSSA BRIDGE

6.1 N. 0.8 W. PARMA, Canyon, ID

Built 1957 Load: 18.0 t ADT: 5,100

STC1762;PRTNEUF RD

Fair

Over: PORTNEUF R;FT HALL MINE

0.2 N. 5.8 W. INKOM, Bannock, ID

Built 1983 Load: 18.1 t ADT: 2,000

SMA 8803;6TH AVE

Fair

Over: PAYETTE RIVER

0.1 S. PAYETTE WCL, Payette, ID

Built 1959 Load: 18.1 t ADT: 1,400

505-3330E

Fair

Over: GRAYS LAKE OUTLET

2.4 S. 27.7 E. FIRTH, Bingham, ID

Built 1947 Load: 18.1 t ADT: 10

200 SOUTH ROAD

Fair

Over: J CANAL

1.0S 1.2E DECLO;970E-200S, Cassia, ID

Built 1984 Load: 18.1 t ADT: 110

STC 2842;E EY ROAD

Fair

Over: RAFT RIVER

2.0 S. 3.2 E. ALMO, Cassia, ID

Built 2001 Load: 18.1 t ADT: 60

GRIMES CREEK ROAD

Fair

Over: GRIMES CREEK

2.9 S. 6.7 W. IDAHO CITY, Boise, ID

Built 1935 Load: 18.1 t ADT: 20

BROWNLEE ROAD

Fair

Over: PAYETTE RIVER;GARDENA BR

AT GARDENA, Boise, ID

Built 1920 Load: 18.1 t ADT: 590

STC3790;ALLENDALE

Fair

Over: LOW LINE CANAL

3.7 S. 2.O E. WILDER, Canyon, ID

Built 1939 Load: 18.1 t ADT: 240

FH 205;CHINA BASIN

Fair

Over: M.FK. BOISE RIVER

0.5 N. ATLANTA, Elmore, ID

Built 1958 Load: 18.1 t ADT: 30

CEMETARY RD

Fair

Over: JIM FORD CREEK

0.6 S. 0.3 E. WEIPPE, Clearwater, ID

Built 1975 Load: 18.1 t ADT: 50

MCDONALD ROAD

Fair

Over: SHEBANG CREEK

5.3 N. 5.9 W. GRANGEVILLE, Idaho, ID

Built 1935 Load: 18.1 t ADT: 20

STC 4721; S RIVER

Fair

Over: COTTONWOOD CREEK

0.7 S. 0.2 W. STITES, Idaho, ID

Built 1964 Load: 18.1 t ADT: 420

HOLMES CROSSING RD

Fair

Over: LAWYER CREEK

4.0 W. FERDINAND, Lewis, ID

Built 1965 Load: 18.1 t ADT: 20

ROCK CREEK ROAD

Fair

Over: RED ROCK CREEK

9.5 S. 6.4 W. KAMIAH, Idaho, ID

Built 1970 Load: 18.1 t ADT: 200

COW CREEK ROAD

Fair

Over: SALMON RIVER;LUCILLE BR

AT LUCILLE, Idaho, ID

Built 1937 Load: 18.1 t ADT: 30

GUERNSEY CUTOFF

Fair

Over: HATTER CR;SW.PRINCETON B

0.8 S. 0.2 W. PRINCETON, Latah, ID

Built 1975 Load: 18.1 t ADT: 30

WEST BEPLATE ROAD

Fair

Over: DEEP CREEK

4.9 N. 1.1 W. POTLATCH, Latah, ID

Built 1970 Load: 18.1 t ADT: 150

3175 NORTH

Fair

Over: WEST SIDE CANAL

IN MOORE, Butte, ID

Built 1989 Load: 18.1 t ADT: 200

STC6807;BIG SPRGS

Fair

Over: BIG SPRINGS;ISLAND PK.BR

4.8 E. MACKS INN, Fremont, ID

Built 1958 Load: 18.1 t ADT: 170

DEADWOOD ROAD

Fair

Over: DEADWOOD RIVER

1 N. DEADWOOD RESV, Valley, ID

Built 1959 Load: 18.1 t ADT: 30

FS ROUTE NO. 257

Fair

Over: STEAMBOAT CREEK

STEAMBOAT CR. @ OMAHO CR., Shoshone, ID

Built 1956 Load: 18.1 t ADT: 50

FDR

Fair

Over: WARM SPRINGS CREEK

6 MILES WEST OF KETCHUM, Blaine, ID

Built 1954 Load: 18.1 t ADT: 50

FDR

Fair

Over: SOUTH FORK BOISE RIVER

MOUTH BIG SMOKY CREEK, Camas, ID

Built 1951 Load: 18.1 t ADT: 50

20082

Fair

Over: WARM RIVER

NO DATA ENTERED, Fremont, ID

Built 1984 Load: 18.1 t ADT: 50

FS ROUTE NO. 208

Fair

Over: CDA RIVER

25.5 MI FROM BABINS JCT., Shoshone, ID

Built 1974 Load: 18.5 t ADT: 50

FS ROUTE NO. 661

Fair

Over: TOOT CREEK

TOOT CREEK, Boundary, ID

Built 1987 Load: 18.5 t ADT: 50

FOREST ROAD 309

Fair

Over: MILL CREEK

2.9 MI. FROM STATE HWY 14, Idaho, ID

Built 1966 Load: 18.5 t ADT: 30

FOREST ROAD 1150

Fair

Over: RED RIVER

NO DATA ENTERED, Idaho, ID

Built 1959 Load: 18.5 t ADT: 10

Showing 351-400 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.