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

FS ROUTE NO. 805

Fair

Over: WEST FORK EAGLE

W FK EAGLE CREEK, Shoshone, ID

Built 1957 ADT: 50

FS ROUTE NO. 805

Fair

Over: WEST FORK EAGLE CREEK

W FK EAGLE CREEK, Shoshone, ID

Built 1957 ADT: 50

NO DATA ENTERED

Fair

Over: OROGRANDE CREEK

PINE CREEK BRIDGE, Clearwater, ID

Built 1950 ADT: 40

FDR 715

Fair

Over: MEADOW CREEK

VIC 5-LAKES BUTTE TRAIL, Shoshone, ID

Built 1985 ADT: 10

PINE CREEK ROAD

Fair

Over: GRIMES CREEK

9.5 MI S.W. OF ID CITY, Boise, ID

Built 1947 ADT: 25

NO DATA ENTERED

Fair

Over: BEAR CREEK

NO DATA ENTERED, Adams, ID

Built 1965 ADT: 50

50234

Fair

Over: COTTONWOOD CK

NO DATA ENTERED, Adams, ID

Built 1966 ADT: 10

NO DATA ENTERED

Fair

Over: E FK WEISER R

NO DATA ENTERED, Adams, ID

Built 1970 ADT: 50

ADAMS CK RD 50025

Fair

Over: MANN CREEK

NO DATA ENTERED, Washington, ID

Built 1953 ADT: 50

LAKE CK ROAD 50104

Fair

Over: LAKE CREEK

NO DATA ENTERED, Idaho, ID

Built 1970 ADT: 50

NO DATA ENTERED

Fair

Over: N FK PAYETTE

NO DATA ENTERED, Valley, ID

Built 1958 ADT: 50

FDR

Fair

Over: EAST FORK SALMON RIVER

22 MILES UP EAST FORK R., Custer, ID

Built 1989 ADT: 50

FDR

Fair

Over: WOOD RIVER

12 MILES WEST SNRA HQDS, Blaine, ID

Built 1953 ADT: 50

FDR

Fair

Over: WARM SPRINGS CREEK

11 MILES WEST OF KETCHUM, Blaine, ID

Built 1991 ADT: 50

FDR

Fair

Over: SOUTH FORK BOISE RIVER

UPPER SO.FK.BOISE RIVER, Camas, ID

Built 1976 ADT: 50

ROAD

Fair

Over: LUCKY DOG CREEK

NO DATA ENTERED, Fremont, ID

Built 1978 ADT: 50

OLD HWY 46;500 E

Fair

Over: CAMAS CREEK

3.2 S. 5.0 E. FAIRFIELD, Camas, ID

Built 1960 Load: 0.0 t ADT: 20

JACKKNIFE ROAD

Fair

Over: JACKKNIFE CREEK

0.9 N. 14.8 E. GRAYS LAKE, Bonneville, ID

Built 1970 Load: 0.0 t ADT: 150

SMILEY C AIRPORT R

Fair

Over: SALMON RIVER

SAWTOOTH CITY AIRPORT RD, Blaine, ID

Built 1950 Load: 0.9 t ADT: 30

STC3024;POLLARD LN

Fair

Over: MIDDLETON CANAL

0.6 N. 1.3 E. STAR, Ada, ID

Built 1967 Load: 3.6 t ADT: 1,300

129TH SOUTH ROAD

Fair

Over: IDAHO CANAL

0.3 E. TAYLORVILLE, Bonneville, ID

Built 1952 Load: 3.6 t ADT: 950

BAYHORSE ROAD

Fair

Over: SALMON RIVER;BAYHORSE CR

8.5 S. 1.2 W. CHALLIS, Custer, ID

Built 1930 Load: 3.6 t ADT: 170

US 20 EBL & WBL

Fair

Over: FARMERS FRIEND CANAL

1.5 E. ST ANTHONY, Fremont, ID

Built 1979 Load: 4.5 t ADT: 9,000

2000 EAST ROAD

Fair

Over: S.GOODING MAIN CANAL

1.7 S. 1.0 E. GOODING, Gooding, ID

Built 1930 Load: 4.5 t ADT: 50

2100 EAST ROAD

Fair

Over: LITTLE WOOD RIVER

0.3 S. 2.0 E. GOODING, Gooding, ID

Built 1930 Load: 4.5 t ADT: 30

LULU STREET

Fair

Over: BIG CANYON CREEK

IN PECK;NE SECTION, Nez Perce, ID

Built 1920 Load: 4.5 t ADT: 50

20160

Fair

Over: WARM RIVER

NO DATA ENTERED, Fremont, ID

Built 1985 Load: 4.5 t ADT: 50

IRR BIA RTE 152

Fair

Over: PORTNEUF RIVER

5KM N OF I-86 AT SR30 EXI, Bannock, ID

Built 1960 Load: 5.4 t ADT: 600

COUNTRY CLUB ROAD

Fair

Over: BIG CREEK;NW.OSBURN BR

1.6 N. 2.6 W. OSBURN, Shoshone, ID

Built 1960 Load: 5.4 t ADT: 200

W 49 S

Fair

Over: GREAT WESTERN CANAL

2.6 S. 5.3 W. IDAHO FALLS, Bonneville, ID

Built 1956 Load: 5.4 t ADT: 230

AIRPORT ROAD

Fair

Over: BEAR RIVER

2.2 N. 1.1 W. DINGLE, Bear Lake, ID

Built 1916 Load: 6.4 t ADT: 50

OGLE LANE

Fair

Over: LITTLE WEISER RIVER

1.0N 1.1W INDIAN VALLEY, Adams, ID

Built 1982 Load: 6.4 t ADT: 50

CAMPBELL LOOP

Fair

Over: LITTLE POTLATCH CR

6.4 N. 3.8 E. GENESEE, Latah, ID

Built 1959 Load: 6.4 t ADT: 70

SPERRY GRADE RD

Fair

Over: POTLATCH RVR(SPERRY BR)

AT KENDRICK SCL, Nez Perce, ID

Built 1908 Load: 6.4 t ADT: 170

GRAVY RIDGE ROAD

Fair

Over: CAMAS CREEK

0.7 N. 11.0 E. DUBOIS, Clark, ID

Built 1956 Load: 6.4 t ADT: 10

STC2815;WARM SPRNG

Fair

Over: BIG WOOD RIVER

IN KETCHUM;WARM SPRING RD, Blaine, ID

Built 1972 Load: 7.3 t ADT: 5,900

1050 EAST ROAD

Fair

Over: BILLINGSLEY CREEK

0.6 N. 1.1 E. HAGERMAN, Gooding, ID

Built 1950 Load: 7.3 t ADT: 50

WILDHORSE ROAD

Fair

Over: WILDHORSE RIVER

10.5 S. 5.9 W. BEAR, Adams, ID

Built 1975 Load: 7.3 t ADT: 30

S. CRANE CREEK RD

Fair

Over: S.FK. CRANE CREEK

9.7 S. 9.1 E. MIDVALE, Washington, ID

Built 1970 Load: 7.3 t ADT: 30

PETERSON RANCH RD

Fair

Over: HAYDEN CREEK

1.2 N. 0.5 W. LEMHI, Lemhi, ID

Built 1955 Load: 7.3 t ADT: 70

1120 NORTH ROAD

Fair

Over: STRATTON CANAL

3.5 N. 1.5 E. RICHFIELD, Lincoln, ID

Built 1950 Load: 8.1 t ADT: 50

STC2739;3800 E. RD

Fair

Over: HIGH LINE CANAL

7 S. HANSEN;3025N-3800E, Twin Falls, ID

Built 1935 Load: 8.2 t ADT: 990

TIMBERLINE ROAD

Fair

Over: E. FK. WOOD RIVER

1.1 E GIMLET, Blaine, ID

Built 1920 Load: 8.2 t ADT: 40

1200 SOUTH ROAD

Fair

Over: CLOVER CREEK

6.9 N. 3.0 W. BLISS, Gooding, ID

Built 1915 Load: 8.2 t ADT: 50

2100 EAST ROAD

Fair

Over: S. GOODING MAIN CANAL

0.9 S. 2.0 E. GOODING, Gooding, ID

Built 1930 Load: 8.2 t ADT: 70

1400 EAST ROAD

Fair

Over: HIGH LINE CANAL

7.5 S. 0.6 W. BUHL, Twin Falls, ID

Built 1915 Load: 8.2 t ADT: 20

S3792;UPPR PLEASNT

Fair

Over: DEER FLAT CANAL

2.0 S. 3.2 E. WILDER, Canyon, ID

Built 1950 Load: 8.2 t ADT: 230

CARLE STREET

Fair

Over: OROFINO CREEK

IN PIERCE; CARLE ST, Clearwater, ID

Built 1974 Load: 8.2 t ADT: 190

SKYLINE LOOP RD

Fair

Over: CLEAR CREEK

4.1 S 4.8 E KOOSKIA, Idaho, ID

Built 1984 Load: 8.2 t ADT: 60

DENVER ROAD

Fair

Over: SHEBANG CREEK

5.3 N. 6.1 W. GRANGEVILLE, Idaho, ID

Built 1935 Load: 8.2 t ADT: 40

Showing 1-50 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.