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

US 93

Fair

Over: U CANAL

12.5 N. TWIN FALLS, Jerome, ID

Built 1984 Load: 33.6 t ADT: 6,500

SH 75

Fair

Over: SALMON RIVER

7.9 S. CHALLIS, Custer, ID

Built 1954 Load: 33.6 t ADT: 1,100

US 93

Fair

Over: GARDEN CREEK

AT CHALLIS, Custer, ID

Built 1941 Load: 33.6 t ADT: 2,200

US 93

Fair

Over: N.FK.SALMON RIVER

IN NORTH FORK, Lemhi, ID

Built 1955 Load: 33.6 t ADT: 1,100

US 93

Fair

Over: N.FK.SALMON RIVER

1.0 N. NORTH FORK, Lemhi, ID

Built 1955 Load: 33.6 t ADT: 730

US 95

Fair

Over: JOHN DAY CREEK

12.4 N. RIGGINS, Idaho, ID

Built 1960 Load: 33.6 t ADT: 2,200

US 95

Fair

Over: SALMON R.;MCKINZIE BR.

7.7 S. WHITEBIRD, Idaho, ID

Built 1969 Load: 33.6 t ADT: 2,200

I 184 EBL CONNECTR

Fair

Over: US 20-26;BOISE RV SLOUGH

IN BOISE; NWCL, Ada, ID

Built 1991 Load: 33.6 t ADT: 27,250

STC 1809; N BEACH

Fair

Over: BEAR LAKE OUTLET CANAL

3.8 E. ST CHARLES, Bear Lake, ID

Built 1968 Load: 33.6 t ADT: 1,200

STC 1847; FIR ROAD

Fair

Over: GOVERNMENT CANAL

1.2 W. SHELLEY, Bingham, ID

Built 1980 Load: 33.6 t ADT: 3,200

STC 1847; W FIR ST

Fair

Over: CEDAR POINT CANAL

IN SHELLEY, Bingham, ID

Built 1980 Load: 33.6 t ADT: 3,200

US 93

Fair

Over: ROCK CREEK

2.5 W. TWIN FALLS, Twin Falls, ID

Built 2011 Load: 33.6 t ADT: 14,500

ORCHARD ACCESS RD

Fair

Over: I 84 EB-WB;MAYFIELD IC

16.4 E. BOISE IC, Ada, ID

Built 1960 Load: 33.6 t ADT: 2,000

STC3814;OLD HWY 30

Fair

Over: CLOVER CREEK;KING HILL

1.5 E. KING HILL, Elmore, ID

Built 1970 Load: 33.6 t ADT: 150

S5752;THOMPSON PAS

Fair

Over: EAGLE CREEK

2.6 E. PRICHARD, Shoshone, ID

Built 1977 Load: 33.6 t ADT: 450

NHS 7553;CAPITOL

Fair

Over: BOISE RIVER

IN BOISE;CAPITOL BLVD, Ada, ID

Built 1931 Load: 33.6 t ADT: 16,000

NHS 7183;9TH ST

Fair

Over: BOISE RIVER

IN BOISE;S. 9TH STREET, Ada, ID

Built 1987 Load: 33.6 t ADT: 15,500

N KRAFT ROAD

Fair

Over: PORTNEUF RIVER

1.0 N. 1.9 W. POCATELLO, Bannock, ID

Built 1945 Load: 33.6 t ADT: 100

BATISTE ROAD

Fair

Over: PORTNEUF RIVER

2.7 W. CHUBBUCK, Power, ID

Built 1968 Load: 33.6 t ADT: 3,300

BERN ROAD

Fair

Over: BEAR RIVER;BERN BRIDGE

0.7 S. 1.7 E. BERN, Bear Lake, ID

Built 1973 Load: 33.6 t ADT: 300

PRESTO RD; E 500 N

Fair

Over: RESERVATION CANAL

0.2 S. 2.1 E. KIMBALL, Bingham, ID

Built 1984 Load: 33.6 t ADT: 140

SANDY ROAD

Fair

Over: GIBSON CANAL

2.7 S. 0.6 W. BLACKFOOT, Bingham, ID

Built 1952 Load: 33.6 t ADT: 100

MCDONALDVILLE ROAD

Fair

Over: PEOPLES CANAL

2.1 N. 0.2 W. GROVELAND, Bingham, ID

Built 1999 Load: 33.6 t ADT: 190

FOUNDRY RD;E 1100N

Fair

Over: RESERVATION CANAL

2.0 S. 1.9 W. SHELLEY, Bingham, ID

Built 1987 Load: 33.6 t ADT: 10

KUPER ROAD

Fair

Over: ROCK CREEK

5.0 S. 1.9 E. ROCKLAND, Power, ID

Built 1939 Load: 33.6 t ADT: 80

620 NORTH ROAD

Fair

Over: MILNER GOODING CANAL

6.0 N. 4.0 W. SHOSHONE, Lincoln, ID

Built 1965 Load: 33.6 t ADT: 340

850 WEST ROAD

Fair

Over: I 84;850 WEST RD GS

2.3 W. BURLEY, Minidoka, ID

Built 1966 Load: 33.6 t ADT: 610

4300 EAST ROAD

Fair

Over: TWIN FALLS MAIN CANAL

2.9 N. 2.4 W. MURTAUGH, Twin Falls, ID

Built 1997 Load: 33.6 t ADT: 30

RIVER ROAD

Fair

Over: CEDAR DRAW CREEK

5.9 N. 3.0 W. FILER, Twin Falls, ID

Built 1999 Load: 33.6 t ADT: 240

3600 EAST ROAD

Fair

Over: HIGH LINE CANAL

7.1 S. 1.0 E. KIMBERLY, Twin Falls, ID

Built 1993 Load: 33.6 t ADT: 80

EMERALD STREET

Fair

Over: I 184B E-W;EMERALD ST GS

0.2 M.W.BOISE WCL;EMERALD, Ada, ID

Built 1968 Load: 33.6 t ADT: 13,000

COLUMBIA ROAD

Fair

Over: MASON CREEK FEEDER CANAL

2.8 N. 0.8 E. KUNA, Ada, ID

Built 1989 Load: 33.6 t ADT: 5,100

BROADMORE WAY

Fair

Over: INDIAN CREEK

IN NAMPA, Canyon, ID

Built 1948 Load: 33.6 t ADT: 20

GALLOWAY ROAD

Fair

Over: I 84;GALLOWAY ROAD GS

4.3 W. CALDWELL, Canyon, ID

Built 1962 Load: 33.6 t ADT: 350

STC 3809;MIDDLE FK

Fair

Over: YUBA RIVER

0.2 S. 1.2 W. ATLANTA, Elmore, ID

Built 1965 Load: 33.6 t ADT: 30

CROOKED RIVER ROAD

Fair

Over: S.FK.CLEARWATER RIVER

0.3 S. 4.4 W. ELK CITY, Idaho, ID

Built 1986 Load: 33.6 t ADT: 110

W. FREEZE ROAD

Fair

Over: DEEP CREEK

2.7 N. 1.6 W. POTLATCH, Latah, ID

Built 1970 Load: 33.6 t ADT: 200

SNAKE RIVER PKWY

Fair

Over: PORTER CANAL

IN IDAHO FALLS, Bonneville, ID

Built 2006 Load: 33.6 t ADT: 1,900

BIRD REFUGE ROAD

Fair

Over: I 15;BIRD REFUGE ROAD GS

2.8 N. HAMER, Jefferson, ID

Built 1963 Load: 33.6 t ADT: 1,100

STC6868;TRAIL CRK

Fair

Over: N. FORK BIG LOST RIVER

17.3 N.E. SUN VALLEY, Custer, ID

Built 1970 Load: 33.6 t ADT: 410

LANDMARK/STANLEY

Fair

Over: ROCK CREEK

24 N. DEADWOOD RESV, Valley, ID

Built 1981 Load: 33.6 t ADT: 30

STIBNITE ROAD

Fair

Over: E.FK. OF S.FK.SALMON RVR

1.5 E. YELLOW PINE, Valley, ID

Built 1959 Load: 33.6 t ADT: 30

ARKANSAS ROAD

Fair

Over: PORTNEUF MARSH VAL.CNL

1.9 S. 0.7 E. ARIMO, Bannock, ID

Built 1957 Load: 33.7 t ADT: 50

NO DATA ENTERED

Fair

Over: DONKEY CREEK

DONKEY CREEK, Shoshone, ID

Built 1952 Load: 33.7 t ADT: 40

FS ROUTE NO. 211

Fair

Over: MEADOW CREEK

MEADOW CREEK, Boundary, ID

Built 1961 Load: 33.7 t ADT: 50

TYNDALL CREEK ROAD

Fair

Over: SOUTH FORK SALMON RIVER

1 MI N OF STOLLE MEADOWS, Valley, ID

Built 1966 Load: 33.7 t ADT: 25

I 15 NBL

Fair

Over: SH 38;MALAD CITY IC

AT MALAD, Oneida, ID

Built 1975 Load: 34.0 t ADT: 6,250

I 15 SBL

Fair

Over: SH 38;MALAD CITY IC

AT MALAD, Oneida, ID

Built 1975 Load: 34.0 t ADT: 6,250

I 90 WBL

Fair

Over: PINEHURST ROAD GS

4.7 W. KELLOGG, Shoshone, ID

Built 2015 Load: 34.0 t ADT: 8,500

US 93; ON RAMP

Fair

Over: US 93

4.7 W. TWIN FALLS WCL, Twin Falls, ID

Built 2011 Load: 34.0 t ADT: 5,600

Showing 2,001-2,050 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.