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

ROAD

Fair

Over: BURNS CREEK

NO DATA ENTERED, Bonneville, ID

Built 1974 Load: 18.5 t ADT: 50

FS ROUTE NO. 314

Fair

Over: BOULDER CREEK

BOULDER CREEK, Boundary, ID

Built 1957 Load: 18.8 t ADT: 50

OKEEFE CREEK ROAD

Fair

Over: CLEAR CREEK

6.5 MI NNE OF LOWMAN ID, Boise, ID

Built 1966 Load: 18.8 t ADT: 10

BEAVER CREEK ROAD

Fair

Over: BEAVER CREEK

NO DATA ENTERED, Custer, ID

Built 1953 Load: 18.8 t ADT: 50

FDR

Fair

Over: WARM SPRINGS CREEK

10 MILES WEST OF KETCHUM, Blaine, ID

Built 1953 Load: 18.8 t ADT: 50

N. PARK DRIVE

Fair

Over: PHYLLIS CANAL

IN NAMPA;W.PARK DRIVE, Canyon, ID

Built 1977 Load: 18.9 t ADT: 320

SUNNY LANE

Fair

Over: PHYLLIS CANAL

IN NAMPA;SUNNY LANE, Canyon, ID

Built 1974 Load: 18.9 t ADT: 1,300

N 2925 E

Fair

Over: FALL RIVER

1.4 N. 0.2 E. CHESTER, Fremont, ID

Built 1963 Load: 18.9 t ADT: 120

US 12

Fair

Over: US 12;SNAKE RIVER

IN LEWISTON AT STATE LINE, Nez Perce, ID

Built 1939 Load: 19.1 t ADT: 19,500

US 20 WBL

Fair

Over: SNAKE RIVER DRY BED CNL

2.3 N. RIGBY, Jefferson, ID

Built 1975 Load: 19.1 t ADT: 9,500

US 20 WBL

Fair

Over: SNAKE RIVER;LORENZO BR.

0.3 N. LORENZO, Jefferson, ID

Built 1974 Load: 19.1 t ADT: 15,000

SH 46

Fair

Over: I 84 EB-WB;S.WENDELL IC

NEAR WENDELL SCL, Gooding, ID

Built 1971 Load: 19.1 t ADT: 7,600

STC 1718;ARBON VLY

Fair

Over: I 86;TRUCKERVILLE IC

8.8 W. CHUBBUCK, Power, ID

Built 1972 Load: 19.1 t ADT: 1,300

STC2866;BASELINE

Fair

Over: A-1 CANAL

3.2 E. RUPERT, Minidoka, ID

Built 1996 Load: 19.1 t ADT: 1,500

STC3830;W ID BLVD

Fair

Over: SEVEN MILE SLOUGH

0.1 SW. LETHA, Gem, ID

Built 1973 Load: 19.1 t ADT: 570

STC4782;GRANGEMONT

Fair

Over: WHISKEY CR.;OROFINO CR.

0.3 N. 2.7 E. OROFINO, Clearwater, ID

Built 1951 Load: 19.1 t ADT: 2,700

SIBERTS OLD RIVER

Fair

Over: FISHHOOK CREEK

2.1 W. AVERY, Shoshone, ID

Built 1935 Load: 19.1 t ADT: 320

S5752;THOMPSON PAS

Fair

Over: BUTTE CREEK

0.9 S. 1.5 E. MURRAY, Shoshone, ID

Built 1977 Load: 19.1 t ADT: 230

S5752;THOMPSON PAS

Fair

Over: BEAR CREEK

1.8 S. 2.7 E. MURRAY, Shoshone, ID

Built 1977 Load: 19.1 t ADT: 230

STC 5805;WESTSIDE

Fair

Over: PARKER CREEK

5.3 S. 0.1 E. PORTHILL, Boundary, ID

Built 1970 Load: 19.1 t ADT: 70

SMA 7406;17TH ST

Fair

Over: IDAHO CANAL

IN IDAHO FALLS, Bonneville, ID

Built 1969 Load: 19.1 t ADT: 24,000

W 1400 S; STRANG R

Fair

Over: LOW LINE CANAL

3.5N. 1.7E.ABERDEEN;1400S, Bingham, ID

Built 1963 Load: 19.1 t ADT: 250

BASELINE ROAD

Fair

Over: SAND CREEK

1.0 S. 2.7 E. SHELLEY, Bingham, ID

Built 1990 Load: 19.1 t ADT: 870

RIVER LANE

Fair

Over: W.BR.LITTLE WOOD RIVER

1.2 S. 0.2 E. CAREY, Blaine, ID

Built 1952 Load: 19.1 t ADT: 50

STC2781;4 MILE RD

Fair

Over: MILNER GOODING CANAL

4.3 N. 2.3 W. SHOSHONE, Lincoln, ID

Built 1965 Load: 19.1 t ADT: 880

1600 EAST RD

Fair

Over: HIGH LINE CANAL

6.3 S. 1.5 E. BUHL, Twin Falls, ID

Built 1968 Load: 19.1 t ADT: 80

SMA 7363;EMERALD

Fair

Over: RIDENBAUGH CANAL

IN BOISE;EMERALD STREET, Ada, ID

Built 1990 Load: 19.1 t ADT: 13,000

SMA9213;VETERANS P

Fair

Over: BOISE RIVER

IN BOISE;VETERANS PARKWAY, Ada, ID

Built 1984 Load: 19.1 t ADT: 21,500

STC 3809;MIDDLE FK

Fair

Over: M.FK.BOISE RIVER(KIRBY)

0.1 N. 1.8 W. ATLANTA, Elmore, ID

Built 1991 Load: 19.1 t ADT: 30

AILOR ROAD

Fair

Over: BIG BEAR CREEK;SW DEARY

0.4 S. 2.5 W. DEARY, Latah, ID

Built 1975 Load: 19.1 t ADT: 50

LITTLE BEAR ROAD

Fair

Over: BIG BEAR CREEK

1.5 N. 0.1 E. KENDRICK, Latah, ID

Built 1959 Load: 19.1 t ADT: 60

ACCESS ROAD

Fair

Over: PARADISE CREEK

AT MOSCOW WCL, Latah, ID

Built 1953 Load: 19.1 t ADT: 20

TWO MILE GULCH

Fair

Over: S.FK.CDA R;TWO MILE CR.

0.4 N. 0.1 E. OSBURN, Shoshone, ID

Built 1966 Load: 19.1 t ADT: 450

2ND SOUTH ST

Fair

Over: BEAVER CREEK

IN DUBOIS, Clark, ID

Built 1941 Load: 19.1 t ADT: 380

SKULL CANYON ROAD

Fair

Over: BIRCH CREEK

0.5 N. BLUE DOME, Clark, ID

Built 2001 Load: 19.1 t ADT: 10

N 2850 E ROAD

Fair

Over: BUTTE MARKET LAKE CANAL

0.2 N. ROBERTS, Jefferson, ID

Built 1931 Load: 19.1 t ADT: 30

FS ROUTE 509

Fair

Over: ST JOE RIVER

20 MI FROM AVERY ID, Shoshone, ID

Built 1954 Load: 19.1 t ADT: 50

CAMPGRD. ACCESS

Fair

Over: SOUTH FORK PAYETTE RIVER

KIRKHAM HOT SPRINGS CG., Boise, ID

Built 1966 Load: 19.1 t ADT: 60

FDR

Fair

Over: EAST FORK SALMON RIVER

28 MILES UP EAST FORK R., Custer, ID

Built 1960 Load: 19.1 t ADT: 50

NO DATA ENTERED

Fair

Over: HAZARD CREEK

NO DATA ENTERED, Idaho, ID

Built 1963 Load: 19.4 t ADT: 50

NO DATA ENTERED

Fair

Over: SMITH CREEK

NO DATA ENTERED, Valley, ID

Built 1972 Load: 19.4 t ADT: 50

IRR BIA RTE 182

Fair

Over: BANNOCK CREEK

14 KM S JCT I-15 & RT 161, Power, ID

Built 1972 Load: 19.6 t ADT: 30

1ST STREET NORTH

Fair

Over: PHYLLIS CANAL

IN NAMPA;1ST STREET NORTH, Canyon, ID

Built 1978 Load: 19.8 t ADT: 2,200

E 100 N RD

Fair

Over: BURGESS CANAL

3.0 S. 0.2 W. LEWISVILLE, Jefferson, ID

Built 1970 Load: 19.8 t ADT: 310

FS ROUTE NO. 1997

Fair

Over: RYE CREEK

8.9 MILES TO AVERY, Shoshone, ID

Built 1949 Load: 19.8 t ADT: 50

NFSR 50432

Fair

Over: N FK PAYETTE

NO DATA ENTERED, Valley, ID

Built 1961 Load: 19.8 t ADT: 50

FDR 60103

Fair

Over: PANTHER CREEK

6 MILES SW OF COBALT, Lemhi, ID

Built 1960 Load: 19.8 t ADT: 50

FDR

Fair

Over: SALMON RIVER

1 MILE SOUTH SMILEY CREEK, Blaine, ID

Built 1957 Load: 19.8 t ADT: 50

FDR

Fair

Over: ALTURAS LAKE CREEK

12 MILES SOUTH OF STANLEY, Custer, ID

Built 1955 Load: 19.8 t ADT: 50

FDR

Fair

Over: SALMON RIVER

4 MILES NE OF STANLEY, Custer, ID

Built 1969 Load: 19.8 t ADT: 50

Showing 401-450 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.