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

150 EAST ROAD

Fair

Over: G CANAL

2.0 S. 1.5 E. BURLEY, Cassia, ID

Built 2001 Load: 50.8 t ADT: 200

STC7839;HAPPY VALL

Fair

Over: NEW YORK CANAL

3.8S 2.4E NAMPA CITY CTR, Canyon, ID

Built 2004 Load: 50.8 t ADT: 660

EAST SHORE RD

Fair

Over: INDIAN CREEK

12.0 N. COOLIN, Bonner, ID

Built 1970 Load: 50.8 t ADT: 110

950 EAST ROAD

Fair

Over: J CANAL

2.5S 1.0E DECLO;240S-950E, Cassia, ID

Built 2015 Load: 51.2 t ADT: 100

NO DATA ENTERED

Fair

Over: OROFINO CREEK

ROSEBUD BRIDGE, Clearwater, ID

Built 1952 Load: 51.2 t ADT: 20

FOREST ROAD 221

Fair

Over: ALLISON CREEK

NO DATA ENTERED, Idaho, ID

Built 1964 Load: 51.2 t ADT: 50

SH 4

Fair

Over: CANYON CREEK;FRISCO BR

2.1 S. BURKE, Shoshone, ID

Built 1999 Load: 51.7 t ADT: 190

US 95 RAMP NBL

Fair

Over: US 95R SBL;LEWISTON IC

AT LEWISTON NCL, Nez Perce, ID

Built 1977 Load: 51.7 t ADT: 4,300

US 26

Fair

Over: TREGO CANAL

0.8 W. BLACKFOOT, Bingham, ID

Built 1989 Load: 51.7 t ADT: 11,500

SH 28

Fair

Over: LEMHI RIVER

13 S. SALMON, Lemhi, ID

Built 2001 Load: 51.7 t ADT: 1,500

SH 28

Fair

Over: LEMHI RIVER

5.5 S. SALMON, Lemhi, ID

Built 2001 Load: 51.7 t ADT: 1,700

US 95

Fair

Over: B LINE CANAL

6.8 S. HOMEDALE SCL, Owyhee, ID

Built 1982 Load: 51.7 t ADT: 3,500

SMA7013;CLOVERDALE

Fair

Over: RIDENBAUGH CANAL

3.0 E. MERIDIAN, Ada, ID

Built 1992 Load: 51.7 t ADT: 19,000

2300 EAST ROAD

Fair

Over: N.GOODING MAIN CANAL

5.2 N. 4.0 E. GOODING, Gooding, ID

Built 1985 Load: 51.7 t ADT: 10

RODEO LANE

Fair

Over: GOLDEN GATE CANAL

4 N. 3 W. WILDER, Canyon, ID

Built 2002 Load: 51.7 t ADT: 270

2ND AVE N

Fair

Over: INDIAN CREEK

IN NAMPA;2ND AVE N, Canyon, ID

Built 1976 Load: 51.7 t ADT: 800

LITTLE ROCK ROAD

Fair

Over: NOBLE CANAL

0.5 N. 2.2 W. LETHA, Gem, ID

Built 1960 Load: 51.7 t ADT: 50

SPINK LANE

Fair

Over: BOULDER CREEK

4.0 N. 1.7 E. DONNELLY, Valley, ID

Built 2004 Load: 51.7 t ADT: 230

BARTLETT ROAD

Fair

Over: BIG LOST RIVER

5.5 N. 19.8 W. MACKAY, Custer, ID

Built 1996 Load: 51.7 t ADT: 110

SH 25

Fair

Over: B-4 CANAL

AT RUPERT SWCL, Minidoka, ID

Built 2001 Load: 52.6 t ADT: 5,900

US 95

Fair

Over: BOULDER CREEK

17.2 N. NEW MEADOWS NCL, Adams, ID

Built 2002 Load: 52.6 t ADT: 2,500

S5779;DICKENSHEET

Fair

Over: PRIEST RIVER

4.4 W. COOLIN, Bonner, ID

Built 1951 Load: 52.6 t ADT: 1,700

STC 6774;N 2400 E

Fair

Over: SALEM UNION CANAL

IN ST ANTHONY, Fremont, ID

Built 1986 Load: 52.6 t ADT: 2,000

SMA 7406;PANCHERI

Fair

Over: PORTER CANAL

IN IDAHO FALLS, Bonneville, ID

Built 1998 Load: 52.6 t ADT: 24,500

BIG BEND ROAD

Fair

Over: PARKER CREEK;MORTER BR

1.5 N. 4.8 W. COPELAND, Boundary, ID

Built 1983 Load: 52.6 t ADT: 30

FS ROUTE NO. 208

Fair

Over: FLAT CREEK

17 MI. FROM BABINS JCT., Shoshone, ID

Built 1974 Load: 53.1 t ADT: 50

SH 24

Fair

Over: MILNER GOODING CANAL

2.5 E. SHOSHONE, Lincoln, ID

Built 2007 Load: 53.5 t ADT: 1,700

SH 52

Fair

Over: NOBLE CANAL

15.7 W. EMMETT, Payette, ID

Built 1990 Load: 53.5 t ADT: 3,200

I 90

Fair

Over: BLUE CREEK BAY WEST GS

6.0E. 4.0S. COUER DALENE, Kootenai, ID

Built 1992 Load: 53.5 t ADT: 17,500

STC 6768;S 600 E

Fair

Over: S. FORK SNAKE RIVER

0.6 E. 2.8 N. RIRIE, Jefferson, ID

Built 1999 Load: 53.5 t ADT: 1,500

STC 6768;S 600 E

Fair

Over: S. FORK SNAKE RIVER

0.6 E. 3.5 N. RIRIE, Madison, ID

Built 1999 Load: 53.5 t ADT: 1,500

PHILLIPPI ST

Fair

Over: RIDENBAUGH CANAL

IN BOISE, Ada, ID

Built 1992 Load: 53.5 t ADT: 1,600

STC 4811;LENVILLE

Fair

Over: LITTLE POTLATCH CREEK

6.0 N. 4.3 E. GENESEE, Latah, ID

Built 1940 Load: 53.5 t ADT: 110

PARADISE RIDGE RD

Fair

Over: S.FK.PALOUSE R;SE.MOSCOW

1.3 S. 0.5 E. MOSCOW, Latah, ID

Built 1978 Load: 53.5 t ADT: 50

I 15 NBL

Fair

Over: STC 1702;WOODRUFF RD.IC

10.3 S. MALAD, Oneida, ID

Built 1975 Load: 54.4 t ADT: 6,500

I 15 SBL

Fair

Over: STC 1702;WOODRUFF RD.IC

10.3 S. MALAD, Oneida, ID

Built 1975 Load: 54.4 t ADT: 6,500

SH 34

Fair

Over: TWIN LAKES CANAL

6.2 N. PRESTON, Franklin, ID

Built 1958 Load: 54.4 t ADT: 1,300

SH 55

Fair

Over: ROUND VALLEY CREEK

3.6 N. SMITHS FERRY, Valley, ID

Built 1933 Load: 54.4 t ADT: 4,200

US 95

Fair

Over: I 90B;NW BLVD;US 95 IC

IN COEUR DALENE, Kootenai, ID

Built 1968 Load: 54.4 t ADT: 13,500

STC 3750;MIDDLETON

Fair

Over: BOISE RIVER

0.6 S. 0.3 E. MIDDLETON, Canyon, ID

Built 2004 Load: 54.4 t ADT: 16,000

STC 4749;OLD HWY 7

Fair

Over: COTTONWOOD CREEK

7.3N. 3.0W. GRANGEVILLE, Idaho, ID

Built 1947 Load: 54.4 t ADT: 820

SMA 7603;BOISE AVE

Fair

Over: RIDENBAUGH CANAL

IN BOISE ON BOISE AVENUE, Ada, ID

Built 1988 Load: 54.4 t ADT: 5,800

BLACKFOOT ROAD

Fair

Over: BLACKFOOT R. & TRAIL CR.

9.7 S. 15.7 E. KIMBALL, Bingham, ID

Built 1985 Load: 54.4 t ADT: 30

S. MTN. VIEW ROAD

Fair

Over: S.FK.PALOUSE RIVER

1.3 S. 1.5 E. MOSCOW, Latah, ID

Built 1987 Load: 54.4 t ADT: 50

E 800 N

Fair

Over: ENTERPRISE CANAL

0.1 N. 2.3 E. CHESTER, Fremont, ID

Built 1986 Load: 54.4 t ADT: 100

I 15 NBL

Fair

Over: I 15B;POCATELLO CREEK IC

IN POCATELLO, Bannock, ID

Built 1999 Load: 55.3 t ADT: 18,750

I 15 SBL

Fair

Over: I 15B;POCATELLO CREEK IC

IN POCATELLO, Bannock, ID

Built 1998 Load: 55.3 t ADT: 18,750

I 15

Fair

Over: BEAVER CREEK

3.0 N. SPENCER, Clark, ID

Built 1969 Load: 55.3 t ADT: 3,500

US 95B

Fair

Over: LAPWAI CREEK

WINCHESTER SCL, Lewis, ID

Built 2002 Load: 55.3 t ADT: 530

STC5711;ST JOE RVR

Fair

Over: MARBLE CREEK

10.8 E. CALDER, Shoshone, ID

Built 1974 Load: 55.3 t ADT: 320

Showing 2,851-2,900 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.