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

I 90 EB-WB;RMP CD

Fair

Over: BNRR;POST FALLS OP

IN POST FALLS, Kootenai, ID

Built 1977 Load: 40.8 t ADT: 60,500

I 90B LOOP

Fair

Over: S.FK.COEUR DALENE RIVER

0.2 E. MULLAN, Shoshone, ID

Built 1973 Load: 40.8 t ADT: 570

SH 75

Fair

Over: BIG WOOD RIVER

3.0 N. SHOSHONE, Lincoln, ID

Built 2013 Load: 40.8 t ADT: 4,700

US 95

Fair

Over: WEISER RIVER

0.2 N. CAMBRIDGE SECL, Washington, ID

Built 1954 Load: 40.8 t ADT: 3,100

US 95

Fair

Over: NPRR;CLEARWATER RIVER

4 N. LAPWAI, Nez Perce, ID

Built 1962 Load: 40.8 t ADT: 6,200

US 95

Fair

Over: HANGMAN CREEK

1.1 S. TENSED, Benewah, ID

Built 1975 Load: 40.8 t ADT: 3,400

US 95

Fair

Over: S. FK. MICA CREEK

9.7 S COEUR D ALENE, Kootenai, ID

Built 2003 Load: 40.8 t ADT: 8,300

US 95

Fair

Over: MOYIE R; UPPER EASTPORT

0.1 S. EASTPORT (CANADA), Boundary, ID

Built 2005 Load: 40.8 t ADT: 550

STC5711;ST JOE RVR

Fair

Over: FALLS CREEK

15.6 E. ST. MARIES, Shoshone, ID

Built 1984 Load: 40.8 t ADT: 900

STC 6774;E 2000 N

Fair

Over: S.FK.TETON R.OVERFLOW

1.2 S. 0.7 E. SUGAR CITY, Madison, ID

Built 1974 Load: 40.8 t ADT: 1,600

NHS 7433;VISTA AVE

Fair

Over: I 84 EB-WB;VISTA AVE IC

IN BOISE, Ada, ID

Built 2010 Load: 40.8 t ADT: 27,000

NHM 7683;ORCHARD

Fair

Over: NEW YORK CANAL

IN BOISE;ORCHARD STREET, Ada, ID

Built 1990 Load: 40.8 t ADT: 18,500

STP8393;FRANKLIN B

Fair

Over: I 84;FRANKLIN BLVD IC

IN NAMPA, Canyon, ID

Built 2000 Load: 40.8 t ADT: 23,500

650 EAST ROAD

Fair

Over: G CANAL

.4S 2.0W DECLO;120S-650E, Cassia, ID

Built 2005 Load: 40.8 t ADT: 100

VICTORY RD;6TH AVE

Fair

Over: ROCK CREEK

VICTORY AVE;TWIN FALLS, Twin Falls, ID

Built 1991 Load: 40.8 t ADT: 1,000

BATT CORNER ROAD

Fair

Over: RIVERSIDE CANAL

3.7 S. 1.3 E. PARMA, Canyon, ID

Built 1997 Load: 40.8 t ADT: 400

CHISHOLM DRIVE

Fair

Over: PHYLLIS CANAL

1.4 N. 0.2 E. NAMPA, Canyon, ID

Built 1996 Load: 40.8 t ADT: 5

HILLTOP ROAD

Fair

Over: I 90 EB-WB;HILLTOP RD.GS

8.3 W. KELLOGG, Shoshone, ID

Built 1967 Load: 40.8 t ADT: 250

COUNTY ROAD

Fair

Over: EMERALD CREEK

2.9 N. 3.3 W. CLARKIA, Shoshone, ID

Built 1973 Load: 40.8 t ADT: 30

CLEAR CREEK RD

Fair

Over: CLEAR CREEK

6.1 W 4.9 S CASCADE, Valley, ID

Built 1966 Load: 40.8 t ADT: 60

W 8200 S

Fair

Over: REID CANAL

1.28 SW ARCHER, Madison, ID

Built 1960 Load: 40.8 t ADT: 20

FS ROUTE NO. 301

Fair

Over: GOLD CENTER CR

5.3 MILES FROM CLARKIA, Shoshone, ID

Built 1986 Load: 40.8 t ADT: 40

NO DATA ENTERED

Fair

Over: E FK WEISER R

NO DATA ENTERED, Adams, ID

Built 1966 Load: 40.8 t ADT: 50

FS ROUTE NO. 208

Fair

Over: CDA RIVER

14.8 MI FROM BABINS JCT., Shoshone, ID

Built 1967 Load: 41.1 t ADT: 40

FDR 711

Fair

Over: QUARTZ CREEK

48 MILES FROM PIERCE ID, Clearwater, ID

Built 1967 Load: 41.1 t ADT: 5

JOHNSON ROAD

Fair

Over: L.W.BR.PRIEST R;MOORE CR

9.0N 3.8W PRIEST RIVER, Bonner, ID

Built 1980 Load: 41.4 t ADT: 20

4100 W

Fair

Over: BIG LOST RIVER

2.5 S. 5.2 E. MACKAY, Custer, ID

Built 1977 Load: 41.4 t ADT: 50

FS ROUTE NO. 1268

Fair

Over: ADAIR CREEK

ADAIR CREEK, Shoshone, ID

Built 1969 Load: 41.5 t ADT: 50

SH 7

Fair

Over: N.FK. CLEARWATER RIVER

AT AHSAHKA, Clearwater, ID

Built 1999 Load: 41.7 t ADT: 2,000

US 12

Fair

Over: COTTONWOOD CREEK

14.6 E. LEWISTON, Nez Perce, ID

Built 1997 Load: 41.7 t ADT: 4,700

US 20 EBL

Fair

Over: S7046;UPRR;SCNCE CTR IC

IF; SCIENCE CENTER DR, Bonneville, ID

Built 1987 Load: 41.7 t ADT: 11,250

US 20 EBL

Fair

Over: FALL RIVER CANAL

0.1 S. CHESTER, Fremont, ID

Built 1994 Load: 41.7 t ADT: 4,500

US 30

Fair

Over: UPRR; SODA SPRINGS OP

NEAR SODA SPRINGS ECL, Caribou, ID

Built 1988 Load: 41.7 t ADT: 3,400

SH 46

Fair

Over: N. GOODING LATERAL 1465

3.5 N. GOODING, Gooding, ID

Built 1986 Load: 41.7 t ADT: 1,400

SH 52

Fair

Over: SQUAW CREEK

12.5 N.E. EMMETT, Gem, ID

Built 1956 Load: 41.7 t ADT: 2,100

SH 58

Fair

Over: N. FK. ROCK CREEK

2.5 E. WASHINGTON BORDER, Kootenai, ID

Built 2008 Load: 41.7 t ADT: 2,400

I 84 ;US 20-26

Fair

Over: BOISE RIVER;CALDWELL BR.

IN CALDWELL, Canyon, ID

Built 1983 Load: 41.7 t ADT: 51,000

I 84 EBL

Fair

Over: UPRR

BOISE SCL, Ada, ID

Built 1969 Load: 41.7 t ADT: 25,000

I 84 WBL

Fair

Over: CO.RD.;GS NO.4

15.8 E. SUBLETT, Cassia, ID

Built 1968 Load: 41.7 t ADT: 5,500

I 84B ;FIRST AVE

Fair

Over: I 84;E.GLENNS FERRY IC

AT GLENNS FERRY NCL, Elmore, ID

Built 1976 Load: 41.7 t ADT: 980

I 90 EBL

Fair

Over: I 90B;THIRD ST.IC

IN OSBURN;THIRD ST.IC, Shoshone, ID

Built 1969 Load: 41.7 t ADT: 6,250

I 90 WBL

Fair

Over: I 90B;THIRD ST.IC

IN OSBURN;THIRD ST.IC, Shoshone, ID

Built 1969 Load: 41.7 t ADT: 6,250

US 95

Fair

Over: PALOUSE RIVER

14.3 N MOSCOW, Latah, ID

Built 2002 Load: 41.7 t ADT: 5,400

SH 3

Fair

Over: ST MARIES R;ST MARIES BR

0.1 S. ST MARIES, Benewah, ID

Built 1977 Load: 41.7 t ADT: 6,900

STC 1843;E 800 N

Fair

Over: SAND CREEK

0.5 N. 2.3 E. FIRTH, Bingham, ID

Built 1982 Load: 41.7 t ADT: 540

STC2810;GANNETT RD

Fair

Over: DISTRICT CANAL

1.1 S. 0.6 E. BELLEVUE, Blaine, ID

Built 1998 Load: 41.7 t ADT: 1,500

STC2863;600 WEST R

Fair

Over: C CANAL

0.6 N. PAUL;040S-600W, Minidoka, ID

Built 1979 Load: 41.7 t ADT: 3,400

STC 3894;CUPRUM RD

Fair

Over: LICK CREEK

1.4N. 19.1W. NEW MEADOWS, Adams, ID

Built 1969 Load: 41.7 t ADT: 80

STC4745;GIFRD RUBN

Fair

Over: COTTONWOOD CREEK

0.6 SE. MYRTLE, Nez Perce, ID

Built 1976 Load: 41.7 t ADT: 520

STC6731;W 145 N

Fair

Over: SNAKE RIVER

9.3 N. 1.4 W. IDAHO FALLS, Bonneville, ID

Built 1967 Load: 41.7 t ADT: 2,600

Showing 2,551-2,600 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.